Transcript Making and decorating pots

Making and decorating pots
Making this pot brief overview
1. Clay prepared
2. Pot thrown on potters wheel then turned
3. Individual pieces dry then glued together with
slip.
4. Pot burnished and a coat of slip applied then
burnished.
5. Decoration planned on paper, then transferred
to pot before firing.
6. Figures blocked out then details painted on.
7. Pot fired some colour added after firing.
Making a pot
• Pottery is made from clay - a sedimentary
rock made up of very tiny particles of
various minerals. The exact composition is
dependent on which rocks were eroded to
form the clay originally.
• Attic clay is unique (but then so are all
clays)- and uniquely suited to a particular
method of potting which the Athenian
potters miraculously discovered and
exploited. Attic clay contains iron – hence
the red colour when fired.
Making and Decorating
Athenian Red Figure vases
•The first stage in making a pot is to dig the
clay out of the ground. Pieces of grit or plant
matter must be removed before the clay can be
used. This was done in ancient times, as it is
today, by mixing the clay with water and letting
the heavier impurities sink to the bottom. This
process could be carried out as many times as
necessary. When judged to be sufficiently fine,
the clay was left to dry out to the required
consistency.
• Collected clay was dried and broken to the
small clod, then rubbish was removed.
After that, it had to be thinned with water
and washed clean of all impurities such as
sand roots. This process was repeated
several times and it was dried to a thick
paste. This was stored in a humid room till
it became sticky enough to throw on the
wheel.
Making and Decorating Athenian
Red Figure vases
• To make a vase the potter kneaded a lump of
clay of suitable size and placed it centrally
on the flat surface of the wheel.
Making a pot
• Scenes on the vases themselves show
that potters' wheels were discs,
presumably made of wood, clay or
stone, about two feet in diameter, with
socketed bases fitting over low, fixed
pivots. It seems to have been usual to
have a boy, presumably an apprentice
potter, to turn the wheel by hand.
• As the wheel
revolved, the potter
drew the clay up
into the required
shape with his
hands.
Making a pot
• Particularly large vases were thrown in
sections, and in the case of shapes
such as cups, the foot would be thrown
separately from the body. The handles
of most shapes were hand-made. When
all the components had been allowed to
dry for about twelve hours, they were
glued together with clay slip.
Making and Decorating Athenian
Red Figure vases
• So how do you get a picture? You make
a pot the regular way, and let it dry a
little ("leather-dry"). Then you mix a
little of the wet clay with a lot of water,
to make a kind of paint (called the slip),
which you use to make the black part of
the picture. (You can't see it now,
because it is all the same color). And
you let the whole thing dry.
Making and Decorating Athenian
Red Figure vases
• The rough outline was drawn on
the clay with charcoal: this
normally disappeared when the
pot was fired, but if the clay was
soft an impression was
sometimes left.
Making and Decorating Athenian
Red Figure vases
• After an initial drawing (probably with
charcoal) the artist has painted in the
complete figure using the refined clay slip
as paint. When fired the details will turn
black.
Making and Decorating Athenian
Red Figure vases
• The second stage was for the
painter to go round the outside
of the figure with a thin brush
(approximately 5mm wide) and
paint a line to enclose the figure
completely. This line can very
often still be detected on the
finished pot. It will of course be
BLACK after the pot is fired.
Making and Decorating Athenian
Red Figure vases
Relief line
• Next comes the detailed drawing within the figures
(represented by the thin dark red line in the picture).
On the finished pot this line is remarkably consistent
in width, and usually "sticks up" in relief.
• We don't know how it was done - whether with a very
fine brush or a syringe special tool (like those used
for icing cakes). The latest theory is that a series of
tools with hairs attached could have been used dipped in the clay paint and laid on to the pot to
make curves, spirals or whatever.
The relief line, drawn with "refined" clay will turn
black after firing.
Making and Decorating Athenian
Red Figure vases
• Now the background is filled in
with black paint using a broad
brush (the reason for the 5mm
line now becomes clear). The
"paint“/ slip is a refined version
of the same clay from which the
pot has been made, and so there
is no great difference in colour
until the pot is fired.
Firing a pot: Black and Red
• Red figure is done all with one type of clay.
The clay found near Athens has a lot of iron
in it, so it looks black when it is wet. But if
you fire it in an oven where there is plenty of
air getting in, the clay rusts, and turns red.
This is because the iron mixes with the
oxygen in the air. If you fire it in an oven with
no air getting in, the iron can't mix with
oxygen, and the pot stays black. So you can
have either red or black pots.
Firing step 1 Oxidising
• In the first stage of
firing, oxidising, plenty
of air was allowed into
the kiln, and the
temperature was
gradually made to rise
to around 800º C. At
this point, the vase
turned a bright orangered, as the oxygen in
the atmosphere
combined with the iron
in the clay to produce
(red) ferric oxide.
Firing step 2 Reducing
• When the potter
judged that 800º C
had been reached,
he shut the air vents
and introduced
damp material in the
form of green wood
or even bowls of
water.
Firing step 2 Reducing
• This produced a
reducing (oxygenpoor) atmosphere in
the kiln and the red
ferric oxide was
converted to (black)
ferrous oxide, so
that the entire pot
turned black.
Firing step 2 Reducing
• The temperature in the
kiln continued to rise to
around 945º C. The
intense heat caused the
fine particles of the clay
of the coated areas of
the pot to 'sinter', that
is, to fuse together to
form a hard, smooth,
almost glassy surface.
Firing step 3
Oxidising
• The temperature was
allowed to drop, and at
about 900º C the
ventilation holes were
opened up, oxygen
returned to the kiln, and
the Black ferrous oxide
of the unpainted areas
converted back to Red
ferric oxide, so that as
the kiln cooled down
these parts turned
orange-red again. The
sealed surface of the
sintered areas does not
let oxygen back in and
so remained black.
• The pot after firing: it will now be
burnished (polished up) and is ready for
sale or use.