photography is combined with other mediums such
as silkscreen, and color is more readily accepted as a
vehicle for photographic artists from the 1970s to
the present.
Kodachrome film was made up of three layers of
emulsion on the film, each sensitive to red, green,
and blue light. This process was the origin of all
subsequent color film. Color film has three layers
of emulsion, each sensitive to one-third of the spec-
trum (red, green, and blue). When the film is
exposed, a latent image is created on each layer
and the development process of color film produces
a multi-layered negative.
The development process of color film creates
the colors in the negative or positive image, nega-
tive if the film is to be used to create a photo-
graphic print; positive if the film is to serve as a
slide or larger-format transparency. Color devel-
oping of film occurs when the developing agent is
added to the film and dye couplers are activated
for each color layer: the area sensitive to red light
forms a cyan image, the area sensitive to green
light forms a magenta image, and the area sensitive
to blue light forms a yellow image. These three
layers are then bleached to remove excess silver,
and a color composite of all three subtractive hues
is formed in the film emulsion. This process is
similar in photographic paper and both positive
and negative color film. The most widely used
process for color negative film is Kodak’s C-41,
which produces a chromogenic color negative cre-
ated by dye couplers. Color transparency film has
a step that reverses the color process and the tonal
range of the film. The standard process for trans-
parency film is Kodak’s E-6, but Kodachrome film
is processed is a slightly different manner, Kodak’s
K-14 process.
Color film is affected by exposure, and over- or
underexposing slides or positive as well as negative
film will change the saturation and value of color.
Transparency or slide film has less exposure lati-
tude than negative film, and is affected more by
exposure variations. Overexposing slide film will
desaturate and lighten the colors in the image,
while underexposing slide film will saturate and
darken the color range of the image. Color nega-
tive film has greater exposure latitude than trans-
parency film, and quality color prints can be
produced from under-and overexposed negatives
that display little difference in hue and saturation
from that of a properly exposed negative. Different
film types and brands can also skew color balance,
and some films produce a warm tone while others
lean more to the cool side of the color spectrum.
Color is also affected by film speed. Fast films have
less saturation, color contrast, and smoothness
than slower color films. Graininess is also an
issue with fast film and this texture increases as
the film’s speed (also known as ISO and ASA)
increases. Slow color film has a richer color palette,
smoother color forms, and a higher contrast than
high-speed film.
Color printing is also a subtractive process. A
negative is placed in a color enlarging head, and
light is projected through the image onto photo-
graphic paper. The filter set of a color enlarging
head allows for different amounts of cyan, ma-
genta, and yellow to be adjusted for color balance.
The strength of each filter is indicated by its density:
the higher the filter number the denser the filter and
the less light permeating through that filter. Color
balance is achieved by adjusting the filter pack on
an enlarger to create an image with neutral shadow
and highlight areas. Viewing filters are useful for
assessing color balance in color prints and are
available in sets of six colors with varying densities
for viewing color prints from transparencies and
negatives. The subtractive primaries are the only
colors used for printing because they make up the
rest of the color scale and also merge to form black
or the absence of light. In color darkroom printing,
yellow is a combination of red and green, magenta
is a combination of red and blue, and cyan is a
combination of green and blue. Thus, the subtrac-
tive printing process in the darkroom allows for all
six colors in the photographic spectrum to be cre-
ated in color prints from negatives or transparen-
cies. Color prints from negatives are often called
chromogenic color prints and use a RA-4 color
process, and color prints from transparencies use
similar processes called Type R, R-3000, or Ilfa-
chrome (formerly Cibachrome). Printing from
transparencies produces a higher contrast image
with more color saturation than printing from
color negatives. Additional color printing processes
used in the color darkroom include dye diffusion
and dye sublimation prints. Color photographic
paper has a variety of qualities, and the paper
type instead of the filter pack used in black and
white printing affects the contrast range of color
paper. Papers are available in a range of subdued
to bright and saturated tones, and the photogra-
pher can choose the type of paper needed based on
his subject matter and vision. By combining color
film types and printing papers, a vast color range is
available for photographers.
Digital imaging follows a similar process utiliz-
ing the additive and subtractive primary colors.
The additive primaries correspond to the CCD
(charged-coupled device) sensors in a digital cam-COLOR THEORY: NATURAL AND SYNTHETIC