In addition to the traditional photographic film and X-ray film, film has also been widely used in the fields of electronic scanning, aviation remote sensing, medicine and industrial diagnosis as the information record storage carrier. Image film made of polymer materials and surface coat of organic photosensitive materials, suitable mold decomposition, especially the surface of the photosensitive film most susceptible to mold invasion. Photographic latex photosensitive film is also prone to hydrolysis due to moisture and damage film image. After mildew, the oxalic acid excreted by mould can corrode silver particles and dye image. The dye image also hydrolyzes itself under high humidity conditions, and the high humidity also causes the residual chemicals on the film to destroy the picture.Harmful gases in the air, such as sulfide and peroxide, can have harmful effects even at low concentrations. Peroxide is the main cause of the oxidation of silver image particles, which leads to colored deposition spots of colloidal silver. Other compounds such as paint volatiles and active compounds can damage the substrate and image, In addition, chemically active dust may discolor the image or leave spots on film. Some having been saved 2-20 years of miniature appeared with subtle color spot or stain, as is due to the partial oxidation of silver image, and come to come to red or yellow spots on the colloidal silver.
Film will also release a gas called acetic acid, under the corrosion effect of acetic acid, the films yellow fisrt began to deteriorate, then start to discolor of all colors and peel off, last film itself is damaged, the process of damage is known as acetic acid dyndrome. Therefore, photographic film not only needs to be moisture proof, but also needs to be kept in a clean environment .
It can avoid images film mold and slow dye fade to be kept ina low humidity environment, but adhesion of subtle and emulsion will be reduced at too low humidity, which cause film edge peeling and emulsion layer cracking phenomenon, and also make the film gray to lost layers.
The ideal long-term preservation conditions of image film is relative humidity 40%, temperature 1-8 degrees with an environment of purifyed air. National standard for preservation of photographic film:
Photo file managemnet standard GB/T 11821-89
6.1.1 preservation appropriate temperature and humidity of film: temperature 13-15℃, 35-45% relative humidity 35-45%.
6.1.2 preservation suitable temperature and humidity of photo: temperature 14-24℃, relativ humidity 40-60%.
6.4.3 the variation of relative humidity in the day and night in the storehouse shall not be greater than +/-5%