Translucent Types for Printing
and put under a weight and blotting paper to dry. When dry pour hot water at about 1600 F. upon the paper till it begins to blister ; then raise one corner carefully with a knife, and strip the paper off, and gently rub the picture with a wet pad of cotton-wool. The paper may be stripped any time after the picture has been on its support thirty minutes, but it is better to let it dry. Lantern slides, plaques, tiles, and lamp shades may all be ornamented in this manner.
Translucent. See Light.
Transparent. See Light.
Trays. Various, extemporised and for travelling, see Dish.
Triangle, Chromatic. An arrangement of the three primary colour elements in the form of a triangle, and by which the com-binations in varying proportions can be seen at a glance. This device seems to be due to Father Castel, who laboured on colour problems some hundred and fifty years ago. Those who are engaged in experiments on the three-colour heliochromy would find it a useful thing to set out a colour triangle. Instructions will be found on p. 46 of The Amateur Photographer for January 18th, 1901.
Tripod. See Camera and Camera-stand.
Types for Printing, originating by photographic methods. Matrices for type-founding are ordinarily made by driving an original steel punch into a mass of copper; and about 1880 Mr. Alfred Dawson successfully applied photography to the pro-duction of matrices from originals sketched on paper, thereby saving the great cost of the original steel punches. In 1900, T. Bolas, at a meeting of the Royal Photographic Society, demonstrated a mode of working; and the following details are taken from a description of the method, which appeared in the Journal of the Society for January 27th, 1900 (p. 118). A typo-graphic plate is first made from the original drawings, the plate is reproduced in stereotype metal, and in making the matrix from a character in the plate, the first thing is to saw out this character from the plate, and then to lay the cut out piece face downwards in the hollow of such a "jig" as was shown, the