colored dye images. These three dye images are controlled by the exposure
time and the color of light that is transmitted.
(1) Controlling the final dye image.
The printed image is
manipulated by exposure and filtration. The combination of the dye images
in the negative plus the filters in the printer control the final dye image
of the print.
(2) Dechroic glass filters. Dichroic glass filters are sharp-cutting
interference filters that completely block out the complementary colored
They have nearly no effect upon the other colors of light.
These filters are far more accurate than CC or color printing (CP) filters.
They attenuate the light by only affecting its specific complementary color
and therefore change the exposure to only a specific emulsion in the print.
(a) This is an advantage over CC and CP filters because the
dichroic filters change the light on only one layer as opposed to CC and CP
that affect all layers and subsequently, the overall exposure.
(b) Adding or subtracting dichroic filters from the filter pack
has very little effect on the overall print density and therefore only a
minimum change needs to be made.
3.
To obtain correct exposure and color balance in a print, exposure must be
controlled to the three individual layers.
The more exposure an emulsion
receives, the more dye is formed and vice versa.
a. Controlling Exposures. The exposure to the red sensitive layer is
controlled by time and intensity.
Since the blue and green sensitive
emulsions are more sensitive to light, a third method of controlling the
exposure is used. This is through filters built into the enlarger.
b. Selecting Filters.
Although cyan, magenta, and yellow filters are
available for use in the enlarger, because of the high sensitivity to light
of the blue and green sensitive emulsions, only magenta and yellow filters
are used.
(1) The magenta filtration will control the exposure to the green
sensitive layer, since magenta absorbs green light.
(2) Yellow filtration is used to control
exposure
to
the
blue
sensitive layer, since yellow absorbs blue light.
3-4
SS0514
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