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 16 th cent. Vasari writes about restoring frescos at Arezzo 18 th – 19 th 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 13 th 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 1.Photo – oxidation 2.Acid migration 3.Biodeterioration 4.Mechanical damage 5.Improper housing 6.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

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

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