Papers, like films, have different characteristics. Some basic knowledge and
common sense regarding the handling of light-sensitive papers will make
your darkroom experiences less frustrating.
Black-and-white papers consist of emulsion on a paper base. Images on
black-and-white films are usually negative or recorded in tones of grey in
reverse of the reflective brightness of a scene. Projecting negative images
onto black-and-white papers results in positive images recorded in tones of
grey relative to the reflective brightness values in the original scene.
Color papers consist of a three-layered emulsion on a paper base. Color
printing papers are for printing color negatives or color transparencies. Like
color films, color printing papers can be identified by the suffixes color for
color prints and chrome for color transparencies.
Photographic printing papers (both in black-and-white and color) are
manufactured in various cut-sheet sizes ranging from 5 by 7 to 20 by 24
inches and rolls up to 1,000 feet long.
Paper characteristics are similar to film characteristics and these
characteristics are emulsion sensitivity, spectral sensitivity, contrast, and
paper surfaces. The performance and use of photographic printing papers
depend on the characteristics of the paper.
Paper emulsion sensitivity refers to the responsiveness of a paper to light.
The emulsions used for printing papers are slower or less sensitive to light
than most film emulsions. A high sensitivity to light is not required or
desirable. Slower paper emulsion sensitivity allows for some exposure
manipulation during the printing process to correct incorrectly exposed
negatives. Exposure manipulation that results in more light given to an area
is called burning in. Dodging is the term used when light is selectively
shielded from specific areas on the paper during exposure.
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