Paper base, surface texture, weight, and size.

LESSON 1

which is sensitive to blue light, the silver halides in the emulsion of

polycontrast paper are "treated" so that some are sensitive to blue light

and others are sensitive to green. The greensensitive halides affect the

low contrast portions of the print and the bluesensitive halides affect the

high contrast regions. This allows the paper to produce varying contrast

responses upon exposure to different colored lights. The photographer,

instead of using different grades of paper, places one of a series of

colored filters under the projection printer lens to achieve a specific

contrast.

(a) Up to ten filters may be available to permit the widest

possible contrast range. The filters are numbered and, in the case of

Kodak's filter kits, range from 1 for very low contrast to 4 for very high

contrast. They range in color from yellow, for lowcontrast, to deep

magenta, for high contrast. When a yellow filter (which absorbs some of the

blue light) is in place, a higher ratio of green to blue halides are exposed

thereby yielding overall lower print contrast. The deeper the shade of

yellow the more the blue light is absorbed, causing lower contrast.

(b) On the other hand, when a magenta filter is used a portion of

the green light is absorbed and we get higher print contrast.

(c) With Kodak filters an average or normal contrast negative is

printed using a No. 2 filter. For a higher contrast negative use No. 1 or

perhaps a No. 0 filter. For negatives which are slightly low in contrast

you might use a No. 2 1/2 or a No. 3 filter.

5.

Paper base, surface texture, weight, and size.

a. The base can be one of two types, fiberbased or resincoated (RC).

There are advantages and disadvantages to both types.

(1) Fiberbased paper produces deeper black tones and more brilliant

whites than RC paper does. In addition, the image produced by fiber papers

will last longer than those of RC paper. However, fiber papers do require

considerably longer processing times. Because the chemicals are absorbed by

the paper base, a greatly extended wash time is required to ensure archival

quality.

(2) Resincoated (RC) papers require very short processing times and

only four minutes for the wash. These papers are ideal for mass production

or when printing a rush work order. RC papers are well suited for areas

experiencing water shortages or operations conducted in the field where

adequate amounts of water may not be available. Due to the lack of

28