Color printing papers are for printing color negatives or color transparencies. Like color negative films, color printing paper can be identified by the suffixes color and chrome. These papers are designed for printing color negatives and color transparencies, respectively.

Like color films, color papers have three emulsion layers. The order of the emulsions is reversed in comparison to color films (fig. 2-8). The top emulsion layer is sensitive to red light and produces cyan dyes, the middle emulsion layer is sensitive to green light and produces magenta dyes, and the bottom emulsion layer is sensitive to blue light and produces yellow dyes.

PAPER SURFACES

Photographic papers are available in a variety of paper surfaces, such as matt, semimatt, lustre, high lustre, pearl, and glossy. The use of different paper surfaces depends on the final application of the photograph. There are two paper surfaces that arc used frequently in Navy imaging facilities: glossy and matt. Paper that has a smooth, glossy surface provides a print with higher contrast and higher densities or color saturations, resulting in an apparently sharper image. This is due to the direct reflection quality of the paper surface (fig. 2-9, view A). Glossy papers are always used for photographic prints that are used to show fine detail, such as equipment damage or intelligence photographs.

Light reflected from MATT paper is diffused and provides a softer, lower contrast image (fig. 2-9, view B). Because of the lower contrast, subject detail does not appear as sharp as an image on glossy paper. Matt papers are used commonly for portraiture and scenic photographs.

PROPER HANDLING AND STORAGE OF FILMS AND PAPERS

Care in handling films and papers prevents fingerprints, abrasions, and scratches on the surfaces of these materials. You should particularly avoid unnecessary contact between an emulsion surface and any other object. Only handle light-sensitive materials by the edges.

Light-sensitive materials should be removed from their packages in a room that is clean, dust-free, and lightproof. The workbench and your hands should be clean and dry. Light-sensitive materials should be

Figure 2-9. Reflection of light of different surface paper.

handled in total darkness or under safelight conditions specified by the manufacturer.

Unexposed light-sensitive materials deteriorate slowly with time even when the materials are stored under ideal conditions. High temperatures and high relative humidity accelerate this deterioration. You should protect light-sensitive materials from the harmful effects of temperature, humidity, x rays, gases, and vapors that may be present in darkrooms, transport, and adverse storage conditions. Storage instructions are printed on the packaging materials of most photographic products.

Kodak papers and sheet film are packaged in humidity-sealed boxes to protect them from changes in relative humidity (RH). Keep these materials in their original packaging until you are ready to use them. When the RH gets at 60 percent or higher for long periods of time, not only do cardboard packages, labels, and metal containers become damaged, but mold, fungus, and bacteria start to grow. Fungi can destroy film and paper by digesting the gelatin in them. Ideally, film and paper should be stored below 50 percent RH.

The usable life of a light-sensitive material varies with the type of material, but generally, color materials deteriorate more rapidly than black-and-white materials, and black-and-white materials with high-speed emulsions deteriorate more rapidly than black-and-white materials with slow-speed emulsions.

Cold storage in a refrigerator or freezer is recommended for all light-sensitive materials; however, refrigerators and freezers that contain food or unsealed containers of liquids have a high relative humidity. Therefore, food should never be stored in the same refrigerator as film and paper.

Paper and professional film should be stored at about 50F (10C) or lower in the original sealed package. All film, including amateur film, must be protected from extreme heat. Never store photographic materials in extreme heat, such as in a glove compartment, trunk, or the back window of a car. Once opened, the original package should be used as soon as possible. After opening, the materials are no longer protected from humidity or chemical fumes.

When film or paper, black and white or color, is removed from cold storage into a warmer atmosphere, allow a warm-up time before opening the original packaging; otherwise, moisture condensation may form on the film or paper. The warm-up time for light-sensitive material depends on the type of material packaging, the size of the package, and the amount of material.

The warm-up times for packages of paper is considerably longer than for film. Paper is usually packaged in larger quantities, 100 to 500 sheets per box and in rolls up to 1,000 feet long. Short roll film and magazines take 1 to 1 1/2 hours to warm-up. Large packages and rolls of film and paper should be allowed to warm-up to room temperature overnight or about 10 hours.