In the first place, a photogram in which there are some large very dark objects, which by reason of their dark colour are disagreeably heavy, or obtrusive masses of deep shadow, may be made to reproduce better if a thin transparent wash of blue be applied to such portions. The great photogenic power of blue is, of course, the reason of this, but until some experience be gained as to the proper amount of blue required, I should recommend that a duplicate untouched photogram be sent in as well, with a few words of explanation and instruction to the process man. If the photogram be upon a glossy surface paper, a few drops of ox gall, procurable in bottles from the artists' colourman, will make the water-colour wash flow readily over the slimy surface.
For working with a brush upon the photogram, the materials are simple and few. Our purpose is to strengthen the lights and deepen the darks, for which purpose Chinese white and two or three water-colours respectively will be used.
The surface and general character of a platinotype or matt paper print will be pleasantest to work on; with an albumenised paper, ox gall will again be essential.
If a liberal amount of hand-work is intended, the print had better be a light one, and it can then be built up to any degree.
Chinese white, when applied thinly, has a bluish hue, and will consequently reproduce somewhat lighter than it appears. Therefore to produce a grey, it will sometimes be better, instead of using thin Chinese white, to make an admixture of Chinese white and Indian ink, or some suitable pigment, and apply it as a grey where grey is wanted. Such portions of the Chinese white which, when dry, appear harsh, may be softened with a clean almost dry sable brush; or the soft part of the finger, with little more than its natural moisture, carefully rubbed over the harsh parts may have the desired effect. By such and any tricks which may suggest themselves it is advisable to blend the hand-work with the actual photographic image.
In applying pigment to the dark parts, to make them darker or sharper, it will be desirable to match the colour of the photographic print as nearly as possible. With platinotypes this may easily be done with Indian ink, with a little blue added according to whether the print is a warm or cold black. The precise colour of a silver print, whether on matt or albumenised paper, is not so easy to match, but may be best accomplished with sepia and cobalt, with a trace of crimson lake; one or two other colours, such as burnt umber, vandyke brown, sienna, &c., being kept in reserve for emergencies. Fine-pointed small sable-hair brushes will be found the best for all purposes.
"STOPPED OUT" PHOTOGRAM.
(Original 6 x 4.)
In the process of reproduction the original may be enlarged upon or reduced. The former is not often attended with happy results, especially if there is much hand-work, but reduction may to some extent be relied on to clear away any trifling blemishes, should such exist. I should, however, lay emphasis upon making the original as perfect as possible; the "improving" effect of the process is an altogether too uncertain and unknown factor to be trusted.