File:The American annual of photography (1914) (14777984444).jpg

Identifier: americanannualof28newy (find matches)
Title: The American annual of photography
Year: 1914 (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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n dyes when mixed with the emulsion render it sensi-tive to the yellow and red end of the spectrum. Plates or films rendered sensitive to the yellow as well asthe blue and green portions of the spectrum are availableand are classed as Orthochromatic. Similarly there areavailable Panchromatic plates which are sensitive through-out the entire spectrum. Curiously enough, a panchromatic emulsion is least sensi-tive to that portion of the spectrum to which the eye is mostsensitive, that is, the yellow-green, so that unlike ordinaryplates which are developed in a light of low luminosity to theeye, (red), a yellow-green, dark room light of good lumi-nosity may be used. Of course, even the yellow-green issomewhat unsafe during the first stage of development, andnaturally the safest procedure is to employ tank development,but generally speaking a panchromatic plate may be handledas readily as the ordinary non-color sensitive one. We are now ready to consider the actual color trans-parency. 120
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CO Take a transparent glass plate and rule one of its surfacesinto rectangles one eighth inch square; then with a fine brushand transparent aniline dyes of the three primary colors fillin the rectangles, coloring them in order red, green, blue, red,green, blue, etc., until the entire surface is a completed Mo-saic pattern. Now take a panchromatic negative plate and assemble thetwo with the emulsion side of the panchromatic plate in closecontact with the colored surface of the above Mosaic colorscreen. Place them in a plate holder with the glass side ofthe Mosaic screen facing out so that when the plate holder isin the camera the light traverses the Mosaic screen before itreaches the panchromatic emulsion. Put a yellow filter in position before the camera lens andexpose. The exposure will probably be from twenty-five to onehundred times that of the ordinary plate, varying of coursewith the dyes used, the speed of the yellow filter and thespeed of the panchromatic emulsio

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