b. Unique Characteristics.
A characteristic unique to internegative
film is that exposure will alter contrast.
The emulsion sensitivity and
construction of internegative film is similar to other color films, except
it has six emulsion layers.
(1) The two top layers of emulsions are sensitive to blue light. The
two center layers are sensitive to green light.
are sensitive to red light. The reason for the double emulsion layers are
for contrast control.
(2) One layer for each color has an inherent low contrast and fast
speed while the other layer has a high inherent contrast and slow speed.
Consequently, if more contrast is required, then exposure is increased; to
lower contrast, decrease exposure. Color balance of the internegative can
be changed by adjusting the filter pack.
Internegative film is designed to be processed in a
normal C-41 process. There are no additives, starters, nor any adjustments
that have to be made. Follow the processing directions in your data sheet
or data guide.
PART B - COLOR NEGATIVE FILM PROCESSING, CHEMICAL MIXING,
Color negative materials and processes have been in use for several years.
Until recently, only a few photographic manufacturers provided the market
with a color negative process. Today, we have a number of makers of color
negative materials with each manufacturer providing the chemistry that is
compatible with their particular product. Although each process is similar,
there is not complete compatibility between films and processes across the
spectrum. In this subcourse, we will standardize one Kodak color negative
film and Kodak C-41 chemistry.
using process C-41.
They break down as follows: four chemical steps, two
water washes, and the drying step. You do not need to memorize the sequence
function of each step.
a. Developer. This is the most important step in the process. There
is only one developer in processing C-41.
The developer reduces exposed
silver halides to black metallic silver, and at the same time, complementary
dyes are formed in proportion to the amount of silver reduced. As silver is