Preserving Photographs

support -- made from any of glass, plastic film, paper, or resin-coated paper
binder -- usually made of gelatin but can consist of albumen or collodion, it holds the final image material or image-forming substance to the support
final image material -- made of silver, color dyes, or pigment particles that are usually suspended in the emulsion or binder layer. Many different final image materials and binders have been used over the years. Today, however, almost all black-and-white photographs are composed of silver suspended in gelatin.

History

	1839-c1860		daguerreotypes
	1839-c1860		salted paper prints
	1851-1890		glass plate negatives (general)
	1851-1885		collodion wet plate glass negatives
	1880-1920		gelatin dry plate glass negatives
	1889-1951		nitrate negatives (introduced by Kodak who ceased production in 1951. Dates of production outside the United States vary.)
	1850-c1900		albumen prints
	1885-1905		gelatin and collodion printed-out photographic prints
	1880-1900		black-and-white gelatin developed-out photographic prints
	1934		acetate negatives introduced for sheet film
	1935		chromogenic color film and transparencies (introduced by Kodak, Kodachrome was the first process)
	1948		instant black-and-white process (introduced by Polaroid. Sepia first, then black-and-white in 1950)
	1960		polyester film introduced
	1963		instant color print process (introduced by Polaroid, Polacolor was the first process. SX 70 was introduced in 1972, Polacolor 2 in 1975)

Deterioration

Four principal factors contribute to photographic deterioration:

presence of residual photographic processing chemicals or the use of exhausted processing chemicals
poor storage enclosures and shelving conditions
rough/inappropriate handling can cause unnecessary wear and tear
poor environmental storage conditions can cause shrinkage, cracking and/or curling

air pollution -- less is best
bright untra violet light -- less is best
fluctuating/high/low relative humidity -- 30% to 50% is ideal
fluctuating/high/low temperature -- 65 F to 70 F is ideal

Handling

When handling photographs or negatives, be sure to follow these guidelines:

hands are clean and dry
wear lint-free cotton gloves
avoid touching the surface
if a photograph must be transported, use some type of sturdy support under it to prevent bending
avoid marking on the photograph, especially with any types of inks or other chemicals
avoid using adhesives

Storage

When storing photographs or negatives, follow these guidelines:

never use enclosures made from unprocessed woodpulp paper, glassine, or polyvinyl chloride (PVC)
avoid products made from colored papers -- they often contain unstable dyes or inks that can cause damage
storage/enclosure material should meet/exceed the ANSI standard specifications IT9.2-1991 (including the Photographic Activity Test (PAT))
purchase storage/enclosure materials from a reputable supplier
for storage, it is best to provide several layers of protection, such as:

place photographs/negatives in appropriate sleeves or envelopes
place into folders
place into boxes

For Additional Information

Books

Taylor, Maureen, Uncovering Your Ancestry through Family Photographs: How to Identify, Interpret, and Preserve Your Family's Visual Heritage, 2000, Betterway Publications, Cincinnati, ISBN 1558705279, $14

Taylor, Maureen, Preserving Your Family Photographs: How to Organize, Present, & Restore Precious Family Images, 2003, Betterway Publications, Cincinnati, ISBN 1558705805, $14

Web Sites

For photograph preservation, click here [photo preservation]
For photograph restoration, click here [photo restoration]
For determining dates of photographs, click here [determine photo dates]
For determining dates of photographs (more), click here [determine photo dates (more)]
For comprehensive information about photographs, click here [comprehensive photo info]