Transcript the perils of paper lecture

The Perils of Paper:
How to Prevent Damage to Collections
Museology and Conservation Training Programme
18 November 2012
Cairo
• The practise of restoration can be traced to
antiquity
• 16th cent. Vasari writes about restoring frescos at
Arezzo
• 18th – 19th cent. Advances in science and new
understanding of the material world
• First changes in attitude towards the preservation of
art
• 1888 The Berlin State Museum
• 1921 The British Museum
• 1930 The Louvre
• 1970 Radical changes in attitude towards the
preservation - less is more: a Minimal
Intervention
Most paper is made from linen, hemp , cotton
and mulberry. Paper is also made from soft
and hard woods
Sizing: an application of adhesive to the
surface of a sheet to make it less porous
and less absorptive. Sizing is also added to
give strength to the paper.
751 AD The art of paper making reaches Bagdad
793 AD Paper-mills in Bagdad
13th cent. Thirty-six libraries in Bagdad, 100 dealers and
publishers
Preservation of Whole Collections NOT a Single Object
The Care and Preservation of Documents and Art on Paper
Step 1. to understand and minimise or eliminate conditions that
can cause damage
Step 2. to follow the basic guidelines for care, handling and
cleaning
Causes of Damage
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Photo – oxidation
Acid migration
Biodeterioration
Mechanical damage
Improper housing
Storage
Photo-oxidation – structural and colour
damage caused by excessive and/or
prolonged exposure to light (over 100 lux)
Signs of Damage:
Yellowing, browning, fading of paper support
Acid Migration – damage due to contact
with acid or reactive materials: wood pulp,
adhesives, rubber bands, certain pigments
that contain or emit harmful acids, or
chemicals that are aggressive.
Watch out for: backing board-wooden,
standard cardboards, mounting board,
pressure sensitive tapes.
Signs of Damage: dark discolouration,
dark or light strips, mat burn, hard-edge
stains where tape has been used as hinges,
pigment acidity where iron gall-ink,
copper green and even orange areas on
highlights or white colours, indicating
presence of lead white has been altered
Biodeterioration – damage caused by mould
growth or insects as a result of high temperature
[above 22C], humidity [above 70%] and lack of air
Signs of Damage: mold growth, foxing, insects
activity
Physical and Mechanical Damage: the
structural weakness due to wrong temperature
and humidity, inappropriate care and handling,
materials used in mounting or storage
Signs of damage: cockling, undulations, tears,
holes, cracked book spines, cracks in paper and
medium due to rolling, distortions at corners
and edges due to tension in mounting or
repairs, rust stains due to clips and staples,
desiccation due to dry atmosphere or heat
Housing and Framing damage: poor quality
housing and backing materials, including
cardboard and wood, lack of window mounts
or fillets in frames, ordinary glass rather than
UV filtering sheets on photographs,
watercolours and prints
Signs of Damage: stains and embrittlement due
to acid migration, undulations due to absorption
of dampness through backing materials,
condensation, water stains, offsetting of
pigments, faded paper and pigments, object
sticking to glass.
Storage Damage:
• inadequate environmental conditions
• unschielded windows
• storage of objects on floor
• on shelves less than 6 inches from floor
• basement storage
• storage in the vicinity of water pipes
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Inadequate air circulation
Overfilled storage boxes
Loose documents, folia or art on paper
Absence of interleaving between works
on paper in folders, storage boxes, mounts
Structurally unstable shelving
Oak shelving
Tight shelving of books
Inadequate fire and flood protection
How to Prevent Damage to Collections
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STORAGE
Relative Humidity 45% - 55%
Temperature 15C – 18C
Daylight excluded from storage
Fluorescent tubes covred by UV-absorbing sleeves
Light level in galleries not exceeding 10 footcandles (100
Lux), best level at 50 Lux. Rotation of works
Air quality – clean. Good ventilation
Storage Materials
Safe materials:
• Rag board
• Acid free paper cardboard
• Glassine
• Polyester film and acrylic sheeting
• Japanese paper (100% Kozo)
• Purified starch paste