Slide 1

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 2

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 3

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 4

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 5

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 6

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 7

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 8

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 9

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 10

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 11

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 12

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 13

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 14

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 15

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 16

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 17

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 18

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 19

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 20

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 21

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 22

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 23

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 24

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 25

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 26

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 27

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 28

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player


Slide 29

Part A Multimedia
Production
Rico Yu

Part A Multimedia Production








Ch.1 Text
Ch.2 Graphics
Ch.3 Sound
Ch.4 Animations
Ch.5 Video

Multimedia








Text
Graphics
Audio information
Animation
Videos

Graphics




Bitmaps
Vector graphics

Reference:
What are bitmap and vector graphics, and how are they different?

Bitmaps
A. Sources of Bitmap Graphics




Scanner
Digital Camera
Screen Captures

Bitmaps


Digitisation
Analog singal



Devices for digitisation:



Scanner
Digital Camera

Digital Form

Bitmaps
B. Comparing to Vector Graphics
1. Easy to create
2. Supported by all browser
3. More realistic

Bitmaps
C. Image Resolution



also called “Image Size”
measured in pixels

References:
HKCityU, Adobe Photoshop

Bitmaps
C. Image Resolution
1.

Aspect Ratio
- Computer screen mostly have this ratio

Aspect Ratio

= Horizontal side: vertical side
= 1024 : 768
=4:3

Bitmaps
C. Image Resolution
2. Digital Camera
Effective number of pixels
= largest picture can obtained

Effective # of pixels
2.0M
3.2M
4.0M
5.0M

Largest picture
1414 x 1414
1789 x 1789
2000 x 2000
2236 x 2236

Bitmaps
C. Image Resolution
3. Printed Size
- Print resolution
- measured by dpi ( dot per inch)
- 300 dpi (minimum )

Minimum Image Pixel = Size of output x 300

Bitmaps




Passport Photo
2” x 1.5”
600 x 450 pixels

Bitmaps




3R Photo
5” x 3.5”
1500 x 1050 pixels

Bitmaps
D. Colour depth
- determine the number of possible colours for each pixel
Colour
depth

Combinatio No. of possible
n
colours for each pixel

e.g. of use

1-bit (B/W)

21 = 2

2 (Black and White)

OCR

8-bit (color)

28 = 256

256 colour

Line arts

4096 colour

Phone mon.

>16M colour

Color photo

12-bit (color) 212 = 4096
24-bit (true
color)

224 =
16,777,216

Bitmaps
E. Graphic file size
Size of bitmap graphics without compression
= Image resolution x colour depth (in byte)

Bitmaps
1-bit black and white
File size
= 640 x 480 x 1 bit
= 307,200 / 8 bytes
= 38,400 / 1,024 kB
= 37.5 kB

Bitmaps
8-bit colour
File size
= 640 x 480 x 8 bit
= 2,457,600 / 8 bytes
= 307,200 / 1,024 kB
= 300 kB

Bitmaps
24-bit colour
File size
= 640 x 480 x 24 bit
= 7,372,800 / 8 bytes
= 921,600 / 1,024 kB
= 900 kB

Bitmaps
F. Compression of bitmap graphics
- reduce storage space
- speed up transmission
Compression ratio = Initial file size : Final file size

Compression ratio  File size 

Bitmaps
F. Compression of bitmap graphics
 Lossy compression





eliminates unnecessary bits of information, like
indistinguishable colours
higher compression  poorer quality
CAN’T get original file back

Low compression

High compression

Bitmaps
F. Compression of bitmap graphics
 Lossless compression





algorithm apply onto the image  reduce file
size
same in reverse (enlarge)
CAN’T control compression ratio

Reverse without loss

Bitmaps
G. Various Forms of bitmap graphics
1. JPG (Joint Photographic Experts Group)






24-bit colour, suitable for photos and complex
graphics
used in digital camera
lossy compression
NOT work in cartoons


Image may lose clarity (清晰) and sharpness (鮮明)

Reference:
What is JPEG graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
2. GIF (Graphics Interchange Format)






256 colours
Better than JPG if images with only a few distinct
colours, such as drawing
Supports transparency
lossless compression

Reference:
What is GIF graphics file format?

Bitmaps
G. Various Forms of bitmap graphics
3. PNG (Portable Network Graphics)




Similar to GIF
256 colours
5 - 25 % < GIF files

Reference:
What is PNG graphics file format?

Article Reading:
What is the difference between JPEG, GIF and PNG?

Vector Graphics
File Size

A.



Depends on the complexity of the picture
Independent of the size of the picture i.e. not the
scale of picture

<
Less complexity

More complexity

Vector Graphics
Creation

B.




Basic shapes, like lines, triangles, circles and rectangle
Software:

Corel® Draw

Adobe® Illustrator

Macromedia® Flash

Macromedia® Freehand

Microsoft® Word

PowerPoint

Limited Tools

Vector Graphics
Converting Vector Graphics into Bitmap
Graphics

C.





use vector-based graphic to export
Screen capture
can’t edit

Vector Graphics
Limitations

D.



with suitable plug-in
e.g. Flash® player