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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CHAPTER III.
MR. II. VOX TALBOT’S PHOTOGENIC DRAWINGS, CALOTYPE, &C.
Section I.—Photogenic Drawing.
of January, 1839, six months prior to the public»-
Daguerre s process, Mr. Eox Talbot communicated to
.^oyal Society his photographic discoveries, and in February
ne gave to the world an account of the process he had devised
tor preparing a sensitive paper for photographic drawings. In
the, memoir read before the Royal Society, he states—" In the
spring of 1834, I began to put in practice a method which I had
devised some time previously, for employing, to purposes of
utility, the very curious property which has been long known to
chemists to be possessed by the nitrate of silver, namely, its dis-
colouration when exposed to the violet rays of light." From
this it appears that the English philsosopher had pursued his
researches ignorant of what had been done by others on the
not necessary to enlarge, in this place, on the
cuts of the two discoveries of Talbot and Daguerre : but it
may be as well to show the kind of sensitiveness to which Mr.
Lawot had arrived at this early period, in his preparations; which
«be best done by a brief extract from his own communication.
is so natural," says this experimentalist, “ to associate the
idea or labour with great complexity and elaborate detail of exe-
cu ion, that one is more struck at seeing the thousand florets of
an Agrostis depicted with all its capillary branchlets, (and so
accurately, that none of all this multitude shall want its little
bivalve calyx, requiring to be examined through a lens), than one
is by the picture of the large and simple leaf of an oak or a chesnut
Dut in truth the difficulty is in botli cases the same. The one
of these takes no more time to execute than the other - for the
object which would take the most skilful artist days or weeks
of labour to trace or to copy, is effected by the boundless powers
natural chemistry in the space of a few seconds." And again
to give some more definite idea of the rapidity of the nrocess’
ill state that after various trials, the nearest valuation which
1 could make of the time necessary for obtaining the pirture of