c. Gamma and X-rays.
Photographers should also be aware of the
undesirable
results produced
by exposing photographic materials to
uncontrolled gamma and X-radiations.
Photographic assignments in areas
where the presence of the radiation is present will usually produce
unsatisfactory results.
The photographer must be aware of their presence
and take the necessary precautions if he is to successfully accomplish his
mission.
PART B - COLOR FILM STRUCTURE, COLOR CONVERSION AND COLOR-
COMPENSATING FILTERS, AND COLOR FILM STORAGE AND HANDLING
Professional photography is far more demanding today than it was a few years
ago.
It is not enough just to know the procedures you must perform to
obtain good results. Today's professional photographer must have a thorough
knowledge of the construction of the film used and the action of the process
to have complete control and consistently produce good results.
9.
Film Structure.
Most modern techniques for color reproduction stem from research on color
vision.
Around 1801, Young and Helmholz advanced the theory that color
vision is based on some system of three-color analysis.
James Clerk
Maxwell, in attempts to prove this theory, used photography to demonstrate
the trichromatic method of color formation.
a. Early Experiments in Color Formation.
Separate records of blue,
green, and red light reflected from a photographic subject presented a
considerable challenge for many years.
Attempts included three sheets of
film exposed through the additive primary filters, through three separate
lenses and filters, a sophisticated prism and mirror camera to split the
light from a single lens, and a tripack or sandwich-like arrangement of
three films. None of these proved practical.
b. Introduction of a Multilayered Film. A multilayer film, coating all
three emulsions on the same film support, would eliminate or minimize the
disadvantages of the other methods. In 1935, Kodachrome film was introduced
and provided this capability. The three emulsions, separated by layers of
gelatin, coated on safety film with antihalation backing are comparable to
ordinary thin black and white emulsions.
This principle is credited for
rapid advancement of modern color photography.
c. Modern Emulsions.
Color reproduction consists of separating and
recording the colored components of light. Modern emulsions are constructed
so that the red, green, and blue light reflected from the subject is recorded
in different layers. Colors, such as skin tones, browns, oranges, yellows,
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