COPYING OLD AND FADED PHOTOGRAPHS.
The chief difficulty in photographing a faded print is the obtaining of sufficient contrast. Not only has the image be come lighter, but the paper, which ought to be white, has become yellow, and this yellow. showing dark in the print, will, with the faded image, conduce to a flat result. The yellowness of the paper may to some extent be counteracted by placing behind the lens a sheet of pale blue glass, which acts as a light filter and obstructs the passage of the yellow rays. The following treatment has been recom mended for strengthening the image. Make np the following solutions : (a) Car last two eases pin up the picture, and ar range to have the light during exposure half on one side and half on the other. When a creased, unmounted print cannot be wetted, it may be ironed flat from the back and placed in the frame. Use a camera which focusses by moving its back part. Focussing should not be done as in general work. The most convenient method of copying is to place the camera (preferably a heavy one) on a table, alongside of which has been pinned down a tape measure. At the one end is a vertical copying board, attached by bent irons. In the centre is a board sliding vertically, and held by a thumbscrew, while the printing frame moves hori zontally in suitable grooves. Camera and copy must always be thoroughly parallel, except when it is desired to cure sonic distortion in the original. It is somewhat
difficult to secure this exact parallelism, unless the camera, and the easel holding the copy. are run on rails or guides.
bonate of lime 4 parts, chloride of lime 1 part, chloride of gold 4 parts, distilled water 400 parts (this is allowed to stand for twenty-four hours before using, is filtered, and must be kept in the dark); (/)) Tungstate of soda 1 part, distilled water 50 parts. For use, take 1 part of n and 50 parts of b. Well wash the prints and place them for ten minutes in the above solution (in which the prints should I assume a purple colour), then transfer the prints to a solution of 2,5 parts of b and 1 part of sodium hyposulphite, which will clean the prints. Slow plates or those specially prepared for photo-mechanical work should be employed, and a strong hydroquinone developer, in order to ob tain a dense deposit with clear shadows. If the image is still too thin and weak, it may be intensified with mercury and ammonia. The contrast may be still further increased by using a slow develop ing paper, such as carbon velox. Strong, vigorous pictures with good gradation may, with a little skilled handwork, be produced from originals that are almost invisible.