What are chromogenic negative and transparency films used for?

Question

And are there any pros/cons of using them?

Answer 1

Slides. The only con is so many people these days don't know what a slide show is and don't have the equipment for it.

The plus is higher resolution and better color retention than typical negatives/prints. A color transparency or slide doesn't lose color over the years. Professional photographers used to prefer slides.

Answer 2

Chromogenic films are not only slide films. Negative films are also chromogenic. The term merely refers to a film in which the colour image is obtained by first forming a silver halide image which is then replaced with coloured dyes. The most common system is the C-41 system developed by Kodak and which is now almost universally used for print films. and the E-6 system used for slide film. Some black and white chromogenic films were/are produced which could be processed in colour chemistry. The cons? The fact that the chemicals have to be disposed of without harming the environment and the silver used in the film recovered for reuse. Otherwise none. Pros - well, since the system covers the vast majority of colour film now sold, fairly obvious.

Answer 3

Chromogenic refers to color photographic processes in which a traditional silver image is first formed, and then later replaced with a colored dye image.

Chromogenic film or paper contains one or many layers of silver halide emulsion, along with dye couplers which are capable of forming visible dyes in combination with processing chemistry. In processing, the silver halide image of each layer is first developed. In concert with the dye couplers in each layer, the process subsequently forms dyes only in those areas where silver is present.

In full-color materials, multiple layers of emulsion are sensitized to different wavelengths of light. Three layers are usually present, generally sensitive to red, green, and blue colored light. Cyan-colored dye is formed on the red-sensitive layer, magenta-colored dye is formed on the green-sensitive layer, and yellow-colored dye is formed on the blue-sensitive layer, following generally the CMY color model.

Some chromogenic black-and-white negative films also exist, mainly to exploit the wide availability of C-41 processing. These films have softer grain and less contrast (more latitude) than traditional silver halide films. In these films, a single emulsion layer has panchromatic sensitivity. The dye image is typically slightly blue because of the choice of dye couplers, and this tends to produce a dark sepia tone when printed on full-color chromogenic paper.

Each microscopic point of chromogenic dye formation is called a dye cloud. After the formation of dyes is complete, the silver image is removed in processing by a specialty photographic fixer called bleach fix or blix. A processing variation called skip bleach, usually applied to motion picture negative processing, allows the silver image to be left partially or completely intact, yielding a type of contrast enhancement.

The most common chromogenic processes are C-41 for color and black-and-white negative film, RA-4 for color negative paper (see Type C print), and E-6 for slide film.

A great deal of research effort has been placed by manufacturers, most notably Fujifilm and Kodak, into controlling the color and tonal characteristics of their chromogenic film and paper. The sensitization of the silver halide emulsions, the composition and mixture of the dye couplers, and the chemical interactions of layers upon one another during processing, are the subject of numerous patents. Fujifilm is apparently unique in its use of a fourth color layer in certain of its negative films.

Like the traditional silver halide process, the main hazardous waste product of chromogenic processing consists of soluble silver compounds dissolved in the photographic fixer.

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