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GENTREK April 8, 2002
Preserve Photographs For Years To Come
Many factors can deteriorate photographs and photographic negatives. Some factors, such as improper processing, are out of our control, but there remain many ways we can take care for our photographs. The following tips will help to insure that our photographs will endure for many years.
The environment can have a destructive effect on photographic materials. Keeping family photographs in the cellar, attic or garage can actually be the worst places to "preserving" them. These environments are subject to excessive heat and moisture, especially in the warmer seasons. Rising and falling humidity causes paper to expand and contract, causing the emulsion to crack. Emulsions can stick together, mold or develop water stains in the event of excessive moisture. :^(
The recommended temperature for storing photographs is between 40 and 65 degrees with humidity levels between 30 and 50 percent. Whether or not you can maintain this ideal environment, reduce the rate of deterioration by storing them in a cool, dry place.
Exposing your photographs to sunlight, or light from fluorescent tubes, allows them to be affected by ultraviolet (UV) radiation. This causes discolorization and fading over time -- especially the case with color photographs.
To help prevent fading, Plexiglas UF-3 sheets can be used in place of normal picture frame glass. However, the ideal prevention is to keep photographs away from windows, so direct sunlight cannot reach them. In the case of tintypes, daguerreotypes, and other types of prints made with earlier photographic processes it is recommended to keep exposure to any light to a minimum, as they can be very unstable.
Insects are notoriously drawn to food but they also eat paper. The gelatin on some black and white prints is especially tempting! Periodically check stored photographs for signs of insects before damage is done.
When framing or removing family photographs from storage, always work with clean hands and clean work surfaces. Wearing cotton gloves prevents fingerprints that will show up years later in the form of deteriorization. When working with photographs that are old or damaged, be sure to use both hands to prevent cracking or tearing the emulsion.
The chemical make-up of many containers and framing materials cause chemical reactions to occur with photographs -- reactions like staining and discoloration. Do not store photographs in a wooden drawer or a cardboard box. Instead, use acid-free photo albums and boxes which can be purchased at art supply or camera stores.
For the photos that were professionally framed, check to see if any of them were assembled with corrugated cardboard or the like. Corrugated board should be noticed and removed immediately! It's effect can be fatal to photographs over time. In the future, request that acid-free mounting and matting materials be used. While these materials may cost a bit more, they are an ideal choice in the preservation of invaluable and irreplaceable photographs.
Digital Scanning for Preservation
Scanning color prints can rarely yield more detail when scanned at more 300 dpi. And in many cases, that number may be closer to 200 dpi. Note these are color prints, to exclude film and B&W prints. In particular, this means typical 35 mm photographic color prints from the photofinisher. Indeed, the original negatives have excellent resolution, a full order of magnitude better than the print copies. Prints vary, some are simply sharper than others.
Then, print size enlargement specifically hurts. Enlarging a film image by a factor of 4 or 8 reduces resolution by a factor of 4 or 8. But mainly, the printing paper itself is far from the equal of the film, it is designed for a different purpose, which does not include additional size enlargement. Good film might resolve detail at 3000 dpi, but color print paper doesnít come close.
There are exceptions to the 300 dpi comment. When scanning 35 mm color photo prints of B&W resolution test targets taken with a good lens on a tripod, 600 dpi scans can sometimes show slightly more resolving power than 300 dpi scans. The results are not nearly double 300 dpi, but perhaps the absolute number is near 400 dpi from good sharp prints.
Scanning a 35 mm negative with a good film scanner is a whole different world where sharp, detailed full page prints become easy. This large difference clearly shows that drastically enlarging a color print is not the best method. Anyone that has ever done any darkroom work knows itís not so easy to create a really sharp 8x10 inch photographic print from 35 mm film. To scan a photo and enlarge it to print at 8x10 on an inkjet is certainly not going to do any better.
Have you ever tried to copy a wallet size photo by photographing the small photo print, and then enlarging that film copy to 8x10? If so, you know its detail will be poor compared to printing from the original negative at 8x10 (and the point is that scanning to enlarge this small print wonít be different). Prints just donít contain the detail to enlarge well. When scanning 35 mm color prints, detectable improvement when scanning over 300 dpi, and often 200 dpi, is negligable.
B&W prints have only one emulsion layer, and might sometimes yield more detail when scanned above 300 dpi. Old historic B&W prints were often contact prints from large negatives (no enlargement at all), which may yield more detail when scanned up at 400 dpi or more, assuming size is needed.
Film can be scanned at 3000 dpi with good effect, because film and film grain were designed to be greatly enlarged. In fact, the only purpose of film is to be enlarged. But photo prints and print grain were not designed to be enlarged. Prints are designed to be viewed by human eye without optical magnification.
Some people discard negatives, but thatís a major mistake. The film is the original master version of the image, and the print is a relatively poor copy.
Photographs are taken to preserve memories and small details that naturally evade one's memory over time. Take the time now to label photographs, thus sharing those precious details with people for generations to come. Try this little tip: Lay a sheet of tracing paper over the top of the photo and note people's names there, rather than on the back of the photo. Use a felt-tip pen so as not to mar the photo. The tracing paper can be folded back to view the picture, and folded down to find out whom it is. This will protect the photo and make it easy to correct. (Writing on the back of a photo causes it to eventually bleed through and ruins the picture.) Use this method to send photos to relatives so they can identify the people they recognize and mail the tissue paper back to you, keeping the copy of the photo.
Following are a few other excellent resources on Preserving Photographs:
Keyword: ROOTS > Resources > "Along Those Lines" Column > The Preservation Place
Keyword: ROOTS > Resources > Library > Lectures 1 > 96-10-13 Native American SIG
(GFS Kevin presents Preserving old documents, photographs and other memorabilia)
Caring for Your Photographic Collections. Library of Congress, September 1997.
Caring for Your Photographs. American Institute for Conservation of Historic and Artistic Works, 1997.
Guide to Preservation Matting and Framing. Library of Congress, 26 June 1996.