Some Basics of Photograph Preservation
Causes of Deterioration
The appearance of daguerreotypes in the late 1830s marks the practical beginning of photography. Many excellent examples of these early photographs still survive. Other photographs, however,—some relatively recent—often show signs of deterioration. This degradation usually results from (1) the chemical makeup of individual photographs, and/or (2) the environment in which photographs reside.
Select Stable Photographs
Black-and-white photographs are more permanent than color images, and is the medium of choice when long-term stability is an objective. Even among color images, however, variations in permanence exist. Kodachrome slide film is a particularly stable color film for long-term dark storage. The quality of photographic processing is also a factor in permanence. Proper photographic processing and thorough removal of chemicals during the final wash are particularly important.
Make A Safe Environment
Proper storage conditions are essential for photograph preservation. A modest investment in archival storage supplies and attention to overall environmental conditions greatly enhances the life of most images.
High temperature and humidity are damaging. Also detrimental are fluctuations in temperature and humidity. A relative humidity of 40 percent and a temperature of 60 to 70 degrees Fahrenheit is reasonable. Exposure to light contributes to image degradation. Ultraviolet light, a major component of sunlight and fluorescent light, is especially harmful. Photographic copies rather than originals are best for long-term display purposes. Photographs are susceptible to damage from fingerprints, tape, glue, ink, rubber bands, paper clips, and various airborne pollutants such as dust and chemical fumes. Protect photographs from these substances.
Chemically inert storage containers are a preservation necessity. Enclosures designated as "acid-free" are not necessarily safe for photographs. Any material that comes in direct contact with a photographic emulsion should pass the Photographic Activities Test (PAT). "Storage Enclosures for Photographic Materials," an excellent technical leaflet published by the Northeast Document Conservation Center, details many of the issues in an easy-to-understand article and provides a list of product suppliers.
Metal shelves with a baked enamel finish are acceptable for holding photograph collections. Avoid the use of cabinets or shelves made of wood, particle board, or press board. Actively used collections should be stored in boxes rather than file cabinets as considerable opening and closing of drawers may cause surface abrasions on the photographic emulsions.
Duplicate Deteriorating Photographs
Make high-quality photographic copy negatives, preferable 4 x 5 inches, of photographs that show signs of fading or discoloration. Fewer photographic labs or studios offer this service due to the emergence of digital technologies, and scanning is rapidly supplanting copy photography. Make duplicate negatives that appear discolored, warped, wavy, or brittle; this process, however, is a highly technical procedure, so employ a conservation facility that specializes in negative duplication.
For More Information
- National Archives web page on preservation, including photographs
- American Institute of Conservation, Photographic Materials Group
- Conservation OnLine
- Northeast Document Conservation Center (not-for-profit conservation lab), Andover, MA
- Etherington Conservation Center (commercial conservation lab), Greensboro, NC
Stephen J. Fletcher, Photographic Archivist
North Carolina Collection Photographic Archives
CB# 3930, 506 Wilson Library
University of North Carolina at Chapel Hill
Chapel Hill, NC 27515-8890
E-mail: click on "Photographic Archives" below