Contact sheet

A contact print is a photographic image produced from film; sometimes from a film negative, and sometimes from a film positive. In a darkroom an exposed and developed piece of photographic film is placed emulsion side down, in contact with a piece of photographic paper, light is briefly shone through the negative and then the paper is developed to reveal the final print.

The defining characteristic of a contact print is that the resulting print is the same size as the original, rather than having been projected through an enlarger.

One or more negatives are placed in intimate contact with a sheet of sensitized photographic paper. The negative and the photographic paper are then placed, negative side down, onto the top transparent glass plate of the exposure box. Within the box and below the top plate is a translucent light diffuser made from frosted glass. Below the diffuser is a switch-controlled electric light source. A hinged top-cover keeps the materials in close contact and reduces or eliminates the amount of stray light allowed into the darkroom. Ansel Adams describes procedures for making contact prints using ordinary lighting in his book, The Print.

The contact printer is used to expose the negative's image onto the paper for a few seconds, creating an invisible latent image on the paper. The operator may use a manual switch and count off the seconds himself, or he may use an electric timer switch.

The black and white gelatin-silver process may be done using a safelight for darkroom illumination. The contact printer may also contain a safelight so that the negative can be examined before the photographic paper is laid upon it.

After exposure, the paper is processed using chemicals in the darkroom to produce the final print. The paper must be placed in a film developer bath, a stop bath, fixer, and finally the hypo-eliminator bath, in that order. Failure to adhere precisely to this process will result in a poor-quality final image with a variety of issues.

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Wikipedia