to photographs can be of a chemical, biological, or physical nature.
In many cases it is not so obvious what causes the damage, especially
not for a layperson. The best advice is to consult a photographic conservator
to check what can be wrong with the print and what can be done.
causes of deterioration are:
temperature and humidity
of the paper support
fungi, bacteria, insects, rodents
fifty year old photograph is slowly being eaten away by bacteria that
live on it's surface. Fortunately we were able to restore it.
Many of these things can be avoided
by proper storage and handling.
deterioration however, cannot be stopped. Only the speed of the deteriorating
process can be reduced by keeping the photographs at the right temperature
with the right humidity level.
temperature and humidity levels are one of the main causes of deterioration.
Photographic materials that are used frequently in reading rooms or
for printing, are especially vulnerable.
of the preservation options is duplication another is digitization.
on modern polyester film garantees a high quality reproduction but is
very expensive, digitization looks very promising.