Practical photography : being the science and art of photography, developed for amateurs and beginners (1881)
Wheeler, Owen, 1859-1932 · London : "The Bazaar" Office · leaf 206
200 PRACTICAL PHOTOGRAPHY. between Vogel's actinometer, where a series of layers of transparent paper forms a gentle gradation to opacity, and the instrument sold by the Autotype Company, in which, when the colour of the silvered paper arrives at one tint, the paper is again moved and another tint… … of sensitised paper, which passes under the orifice of the face and out through the side, as shown in the illustration. The application of the photometer to carbon printing ought to be pretty obvious. By preliminary test it is found what tint on the face registers the correct exposure of the tissue…
Photography
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