Photographic Prints

Traditionally, linen rag papers were used as the base for making photographic prints. Prints on this fiber-base paper coated with a gelatin emulsion are quite stable when properly processed. Their stability is enhanced if the print is toned with either sepia (brown tone) or selenium (light, silvery tone).
Paper will dry out and crack under poor archival conditions. Loss of the image can also be due to high humidity, but the real enemy of paper is chemical residue left by photographic fixer. In addition, contaminants in the water used for processing and washing can cause damage. If a print is not fully washed to remove all traces of fixer, the result will be discoloration and image loss.

• Fixer (Hypo)—A chemical, sodium thiosulfate, used to remove residual silver halides (grain) from films and prints when processing them. Fixer "fixes" the remaining silver halides in place on either film or prints. Fixer is also called hypo.

The next innovation in photographic papers was resin-coating, or water-resistant paper. The idea is to use normal linen fiber-base paper and coat it with a plastic (polyethylene) material, making the paper water-resistant. The emulsion is placed on a plastic covered base paper. The problem with resin-coated papers is that the image rides on the plastic coating, and is susceptible to fading. At first color prints were not stable because organic dyes were used to make the color image. The image would literally disappear from the film or paper base as the dyes deteriorate. Kodachrome, dating to the first third of the 20th century, was the first color film to produce prints that could last half a century. Now, new techniques are creating permanent color prints lasting 200 years or more. New printing methods using computer-generated digital images and highly stable pigments, offer permanency for color photographs.