In some color films where tabular-grain (T-grain)
emulsions are used, high speed and increased sharpness
are combined. When these films are manufactured, the
overall thickness of the film is reduced By reducing the
overall thickness, you also reduce the scattering of light
within the film, resulting in improved sharpness. Also,
double-emulsion layers, one fast and one slow, may be
incorporated to improve film speed in color films.
Each emulsion layer of color film either has an
incorporated dye coupler or a dye that is put into the
emulsion during processing. A dye coupler is a chemical
that produces a dye by combining with the oxidized
products that occur during color developer.
Color Negative Film
A color negative film records a scene in image
densities opposite to the brightness of objects in the
scene-the same as a black-and-white negative film.
Color films can be recognized because they contain the
suffix color, such as Vericolor, Kodacolor, and
Fugicolor. These color films are used when a print is the
final product. Most color negatives (other than color
film used for aerial photography) have an orange mask
This orange mask increases the color separation that
reproduces colors more accurately in the final print.
During development, colors are formed in the
emulsion that are complementary to the color of the
original scene; for example, a red object in the scene is
recorded as cyan in the negative. It is a combination of
yellow, magenta, and cyan that records all the other
colors that you see in the scene. Color dyes in the
emulsion layers control the colors of light passing
through the color negative.
Color negative film images can be printed on color
positive materials, such as color paper and color print
film, to produce color prints or color transparencies.
Color negatives can also be printed on a special
panchromatic black-and-white paper to produce
Color Reversal Film
Color reversal films produce positive images in
densities directly proportional to the reflective
brightnesses of objects and in the same colors as those
in the original scene. Reversal films are recognized by
the suffix chrome in their names, such as Ektachrome,
Kodachrome, and Fujichrome.
The positive image of most color reversal film is
produced by a two-stage development process. This
process causes chemical fogging and color developing
of the portions of the silver halide emulsions that were
not affected by camera exposure or the first
black-and-white developer. Like color negative film,
color reversal film has three emulsion layers that are
sensitive to blue, green, and red light and produces
yellow, magenta, and cyan dyes, respectively. The film
contains dye-forming chemicals that are put into the
emulsion layers during manufacturing. A color
developer produces three dye images in the emulsion
layers. The three dye images in a developed color
reversal film control the colors of light passing through
Kodachrome film does not contain dye-forming
chemicals in the emulsion layers. They are introduced
during processing from three separate color developer
solutions. Kodachrome film has high resolving power
and tine grain and produces a fine image. Processing
Kodachrome film is a complex operation and can only
be performed by a Kodak processing plant.
Developed color reversal film can be used as a
transparency (slide) for direct viewing, printed directly
onto a color reversal paper, copied on a black-and-white
film for producing black-and-white prints, or copied to
a color internegative (copy negative) for producing
Color balance is the acceptable relationship among
the three color images in a positive color print or slide.
This means that when the color print or slide looks
correct, color balance has been achieved.
To help achieve this acceptable relationship, the
manufacturer balances color film emulsions for
exposure with a specific Kelvin temperature (K).
Remember, daylight usually has a higher content of blue
light than red light, while tungsten illumination usually
has a higher content of red light than blue light. To
compensate for the lower proportion of red light in
daylight, the manufacturer balances color films for
daylight, so they have a higher sensitivity to red light
than to blue light. To compensate for the lower
proportion of blue light in tungsten illumination, the
manufacturer balances color films for tungsten
illumination, so they have a higher sensitivity to blue
light than to red light.
Generally, color films are referred to as daylight
(outdoor) or tungsten (indoor), indicating their broad
use without filters. Specifically, daylight films are
balanced for use in sunlight or with an electronic flash