An introductory website exploring the art and science of photograph conservation and restoration.
An introductory website exploring the art and science of photograph conservation and restoration.
Conservation treatments range from very simple tear repairs or flattening to more complex treatments such as unmounting, washing, and stain removal. Treatments vary widely depending on the photographic process and the use of the photograph whether as an archival record, fine art print, or family heirloom.
Cleaning of photographs varies with the type of photograph and the type of grime, accretions, and dirt that have built up on the surface over time. Dry cleaning materials such as erasers are sometimes appropriate and some dirt is soluble in organic solvents that can be carefully applied with cotton swabs. Dry cleaning materials can be abrasive though as the surface of the photographic print can be quite delicate especially if it’s compromised by age and deterioration. Organic solvents can be very good at removing certain kinds of dirt, but they can also cause silver fading and discoloration, or even dissolve the image with certain types of prints and negatives.
Cockling and waviness occur with many types of photographs over time or as the result of accidental contact with water such as in a fire or flood. Flattening usually begins with the controlled addition of moisture to a photographic print. This humidification allows the paper support and image binder to soften and expand. The print is then dried by pressing between sheets of non-woven polyester and blotter paper that are changed regularly until the print is completely dry. As the print dries in this “blotter stack” it is kept flat by keeping a heavy weight on the top of the stack. When the print is dry it is also flat.
Tears happen to photographic prints just like with any piece of paper. Mending the tear with Japanese paper and wheat starch paste is the most common solution. The Japanese paper is typically made from Kozo fibers which are strong and long fibers giving great strength to even a thin piece of Japanese mending paper. The wheat starch paste has a long history in conservation and is one of the most stable adhesives known. It remains water soluble even after hundreds of years so the mends can be removed without causing further damage.
When a photograph is stained and yellowed by age and light exposure or stained by a coffee spill only washing in aqueous solutions can effectively reduce such stains. However, water can also cause damage to photographs especially if the image binder was ever exposed to mold, which makes the gelatin binder much more soluble in water. In addition, water can cause inks and stamps to bleed and can lead to fading and degradation of a silver image. There are many more complications that can arise from the use of water, so washing and stain removal is never undertaken lightly.
Sometimes there are losses in an image or there are stains that cannot be safely removed by cleaning or washing. The only way to reduce the appearance of these losses and stains is to retouch over them with a variety of paints, pigments, and coatings. This is done by a photograph conservator so that the retouching materials can always be safely removed without affecting the original photograph. This approach is referred to as “reversibility” in conservation, and while not every treatment is reversible (washing for instance cannot be undone), it is a principle we strive to achieve as much as possible in order to preserve the integrity of the original object.
The adhesives, coatings, cleaning agents, mending papers, and other materials used by photograph conservators in the treatment of photographs are limited to those that have been tested to not cause any harm to the photograph even in the long-term. For example. some adhesives cause fading of a silver-based image over time. Conservation materials and enclosure materials like paper sleeves can be tested for their safety in contact with photographs by the Photographic Activity Test (PAT). The PAT was developed at the Image Permanence Institute, which continues to perform the PAT today according to the specifications outlined in the international standard ISO 18916:2007 Image materials – Processed imaging materials – Photographic activity test for enclosure materials.
