A Manual Of Photography
Forfatter: Robert Hunt
År: 1853
Forlag: John Joseph Griffin & Co.
Sted: London
Udgave: 3
Sider: 370
UDK: 77.02 Hun
Third Edition, Enlarged
Illustrated by Numerous Engrabings
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196
PRACTICE OF PHOTOGRAPHY.
or yellow paper, it will be evident that the highest lights will be
represented as dark portions, and the shadows as lights. Thus
we obtain a negative image. The female figure in the adjoining
woodcut, Fig. 39, is copied from a calotype negative portrait; and
the negative being used by superposition on another prepared
piece of paper, produces a positive in which the lights and shades
are natural, as in the second figure, Fig. 40.
80. 40.
Let us commence by supposing the experimentalist to be
supplied with paper prepared by some one acquainted with the
manipulation, and that he is now to observe for the first time
the effects produced.
For the production of photographic drawings, it is necessary
to be provided with a copying frame and glass, the most conve-
nient size for which is something larger than a single leaf of
quarto post writing paper. The glass must be of such a thick-
ness as to resist some considerable pressure, and it should be
selected as colourless as possible, great care being taken to avoid