(c) The unique advantage of this technique is that the dye coupler
is mobile; thus, dye formation can take place at the site of silver image
formation because coupler molecules are available to react with the oxidized
developer molecules. This results in greater resolution and an almost total
lack of graininess.
11.
Exposing Color Films.
Exposing and processing color films, whether negative or reversal, is
basically the same as that for black and white. Because of the more complex
construction of color films and more steps in processing, there are certain
differences between them.
Exposure, quality of exposing illumination, and
processing times and temperatures are much more critical than with black and
white films.
12.
Exposing Illumination.
The eye automatically adjusts for changes in the color quality of light
sources. Color films, unfortunately, do not have this capability. They are
constructed to meet lighting situations having specific spectral qualities.
Therefore, a color emulsion will most accurately reproduce the colors of the
subject only when exposed under illumination for which it is balanced by the
manufacturer.
a. Producing a Satisfactory Color Balance. Spectral quality refers to
the various combinations of wavelengths present in the light source.
Daylight color films, therefore, must receive equal amounts of these
radiations to produce a satisfactory color balance.
(1) Daylight contains approximately equal amounts of red, green, and
blue. Daylight color films, therefore, must receive equal amounts of these
radiations to produce a satisfactory color balance.
(2) Electronic flash is often used as the sole light source for
indoor scenes. However, it is just as useful outdoors even when the sun is
shining. It can be used to either fill in shadows or to simulate sunlight
under hazy skies.
Electronic flash approximates natural sunlight
conditions. The color flash is suitable for daylight-balanced color films.
(3) Tungsten illumination is comparatively high in red content and
deficient in blue wavelengths.
Therefore, tungsten color films have a
relatively higher blue sensitivity. Due to this increased blue sensitivity,
if exposed under daylight conditions, tungsten reversal emulsions will have
an excessive bluish cast. On the other hand, daylight color films appear
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