File:The American annual of photography (1911) (14596763730).jpg

Identifier: americanannualof1911newy (find matches)
Title: The American annual of photography
Year: 1911 (1910s)
Authors:
Subjects: Photography
Publisher: New York : Tennant and Ward
Contributing Library: Harold B. Lee Library
Digitizing Sponsor: Brigham Young University

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Next in order ofbrightness comes the red, while the blue is of still lesser lumi-nosity, and reflects very little indeed compared to the whitepaper; for the sake of clearness let us give numerical valuesto the colors which will be represented about as follows: White paper lOO Yellow patch 50 Red patch 40 Blue patch 10 Considering now the cut-out on the negative through thered filter we obtain the highest opacity on the portion cor-responding to the white; next in order comes the yellow whichalso acts strongly upon the pate, because the yellow (whichis composed of green and red light) is first transmitted whollyin the red and partially in the green by the filter, and second,because the plate used is sensitive to these hues; in other words,the plate is being acted upon by the combined effect of twohues and to both of which it is strongly sensitive, so that theonly reason why this color does not impress itself as stronglyas does the white (which is also acting with but the same num- 274
Text Appearing After Image:
o I—I H<PiOL)WQ WPQ ber of hues) is because of the loss of light in the reflectionfrom the layer of ink. The red patch is fully transmitted bythe filter, and acts upon the plate with light of one hue, theblue which the ink reflects being absorbed by the filter, henceit is not represented by so strong a deposit. Suppose that a certain patch of magenta red reflected 50units, together with a portion of the green, plus the strongergraphed through the red filter the 50 units of blue would bedefinitely absorbed, leaving only the 50 red units to afifect theplate, obviously one could not expect equal action comparedto say—the white paper which has 100 per cent, active redunits, together with a portion of the green, plus the strongerreflection of the hues from the unprinted paper. The cut-out action of the green filter is (generally speak-ing) subjected to more adverse criticism than either of theother two, chiefly because the operator is not sufficient of acolor student to appreciate h

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