(Original 4½ x 3½.)
It seems scarcely necessary to refer to the use of water colour and oil paintings in colour as illustrations, inasmuch as if produced for purposes of reproduction, colour would hardly be employed. Occasionally, however, one may require to make a photogram of a painting for some such purpose, in doing which it will be best to employ a professed photographer who is accustomed to copying, and this because the photographing of coloured objects possesses peculiar difficulties.
Plates known as "Isochromatic" are used, these having certain dyes mixed with the sensitive film which makes them more sensitive to the least active colours, such as reds and yellows, and in addition a stained film of gelatine or glass is introduced into the lens to further correct the action of the colours. Special care, too, in lighting the picture to be copied is requisite, some experts recommending the use of coloured reflectors.
If the greens, reds, and yellows are not very pronounced, or the effect is not greatly dependent upon blue and such hues which by reason of their great light activity photograph as white, a fair copy photogram may be produced under ordinary circumstances; but where any doubt exists, I should recommend that the work be done by an experienced operator.
Throughout the foregoing remarks on the half-tone process, it will have been gathered that its inherent defects constantly stand in the way of our giving it unqualified approval. A recent writer on the subject, Mr. C.G. Harper, says of half-tone process that it is "inconstant and for ever incapable of rendering wash drawings as well as the wood-engraver."
Be this as it may—and it may not be possible to gainsay it—each day sees such improvements made in the processes, that even before these sheets are in my reader's hands circumstances may require a change of opinion, and prejudices may have given way under the convincing influences of modern improvements.
We may now turn our attention to the more direct processes of reproducing in line, in which, more than in any other direction, the revolution which photography has brought about in the art of illustration is evident.
