Some examples of physical deterioration are holes, scratches and spots that are caused from the abrasion of one material against another. Brittle matte board or photographs can snap and create losses in the image area. Glass plates when not handled properly can chip or break. Water can destroy a photograph. Folds in paper weaken the internal structure and are a source for significant damage.
Biological deterioration is the fourth form of paper products deterioration.
Photographic materials especially contain ingredients such as gelatine and cellulose in paper that are attractive to insects and rodents. Insects will actually chew away pieces of prints and even containers especially when they are moist. The most important factor affecting the preservation is the storage and display conditions to which they are subjected. This includes the material in which they are enclosed, where they are stored and the manner in which they are displayed. Processed negatives, slides and photographic prints should be enclosed in special envelopes, sleeve files, or albums to protect them from dirt and physical damage and to facilitate identification and handling.