PHOTOGRAPHY IN COLOURS.
[To THE EDITOR OF THE "SPECTATOR."] SIR,—Will you permit me a few words of comment on the very interesting article on "Photography in Colours" which appeared in last week's Spectator ? I quite agree with the view the writer takes about the artistic value of the process and its probable results, though what he says applies almost equally well to monochrome photography. I do not agree with his statement that photography has driven the artist out of the illustrated papers and magazines. What it has done has been to abolish the wood engraver, the artist's original work being now, I think without exception, repro- duced by photographic means.
The only fault I find with the writer of the article is that be does not refer to what is really the most important point in all the practical processes of colour photography,— namely, that the colours are not in any sense the colours of Nature, but an approximately correct translation of natural colours by means of pigments. Colour is, of course, an entirely subjective phenomenon. The infinite variety of light-waves impinging on the retina produce in the brain what we know as the sensation of colour. The retina appears to be only capable of discriminating between three groups of these waves, giving the sensations red, blue, and green. Mixtures of these in -various proportions give us the whole colour scale. If, therefore, we can substitute for the gradations of the natural colour gamut the three
colours to which the eye is sensitive, we can reproduce the sensation of any colour whatever. This we do by sifting the light reflected from natural objects through three coloured screens, which are, or ought to be, of the same colours as those to which the eye is sensitive. To do this with absolute accuracy the colours of the screens ought presumably to be identical with those to which the eye is sensitive, and we do not really know what those colours are. What knowledge exists on the subject is, after all, empirical, and the precise colours would most likely vary with each individual. Research and experiment have probably given us a very close approximation to the truth, but even now there are variations of opinion as to the precise tints which give the best results. These best results are, therefore, only approximate, and the approximation varies very considerably.
The writer of the article speaks of "doctoring" the auto- chromes. My experience of the process is not sufficient to justify my laying down the law about it. But I am pretty certain that no doctoring of the autochromes is possible, except so far as it may be effected by varying the exposure. Of course, monochrome photographs are doctored and " faked " up to almost any extent, but the alterations are almost wholly in the printing processes. In the three-colour process of printing (by which the autochromes are repro- duced) any amount of doctoring is possible; in fact,. I suppose there can hardly have been a three-colour print made which was not altered or modified to a very con- siderable extent in the process of reproduction. This, of course, increases largely the artistic possibilities of the process, but it does not tend to absolute truth.—I am,