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Precautions to be Observed in light

The chemicals used to produce it are Making a Picture. When directions are also combinations of the salts of silver, but given to prepare and keep the sensitive paper are so sensitive to the action of light, that in a dark room, it should, of course, be under- they are decomposed instantaneously by exstood that daylight only is to be excluded; posure. The formule will follow a descripgas or candle light will do no harm. A window tion of the process. closely covered with yellow paper completely 3143. To Make a Photographic filters the light of all actinic or chemical Negative. In a room illuminated only by a power, and consequently will do no harm. feeble gas or candle light, or by such daylight Be careful that not a drop of the fixing solu- as is filtered of its chemical power through tion gets into the gold or toning bath. After a sheet of yellow glass, a glass plate is carethe final process of fixing, take the greatest fully flowed with collodion. (See No. 3149.) care that the prints do not again come into When the plate has been evenly covered, the contact with the hyposulphite of soda. Soda excess is quickly but deliberately returned to is good-indispensable in its place, but ex- the bottle, and the plate gently and slowly ceedingly harmful out of its place. So keep swayed from side to side until the collodion is all the dishes and fingers free from it. In all set, or when the surface is tacky to the touch. of the manipulations, observe the most perfect It is then placed on a dipper, and, with a neatness. Handle the prints with the tips of steady, continuous motion, immersed, colloyour fingers, and always with deliberation dion side upwards, in the silver bath. (See and care.

If the silver solution grows weak No. 3150.) If the plate is stopped in its deby use-a mealy look to the prints indicates scent into the bath, a check or line will show it-add a few grains of nitrate of silver. If across its face. In 3 to 5 minutes, depending by use it turns a dark wine color, and the upon temperature, etc., the plate is coated, paper is not white when dry, set the solution or, in other words, the chemicals in the colloin clear sunlight for a day or two and it will dion have united with the nitrate of silver, clear. Filter before using again. The soda forming the sensitive surface or coating, If (fixing) bath should not be used more than 2 not coated sufficiently the surface will appear or 3 times. Where prints are only occasion- greasy; in this case the plate must be returned ally made, a fresh bath should be made each to the bath until the film appears perfectly time of printing. The gold (toning) bath smooth. While this is being done it is supworks quicker when warmed to about blood posed that the operator has adjusted the heat, Prints will then tone in from 2 to 6 camera upon the object to be photographed minutes. Prints on plain paper will tone by focussing his lens. This is done by turnquicker than on albumenized. If prints are undertoned they will present a warm brown appearance; if toned too much, a cold steel color. A little experience will soon indicate the precise amount of toning required. ing the lens in and out, or from and towards the ground glass of the camera, until the point is ascertained which gives the sharpest image upon the ground glass. All being ready, the operator returns to the dark room 3141. To Remove Nitrate of Silver for his sensitive plate. This is placed in a Stains. An inevitable consequence of prac- "holder," and the ground glass being reticing this process will be stains on the hands moved, the holder is substituted in its place. and clothing from the nitrate of silver. The slide or cover to the holder is now with- Moisten the spots with tincture of iodine, and drawn and the sensitive plate exposed to the then with a saturated solution of hyposul-action of the image of light thrown upon it by the lens. After an exposure of 15 to 60 sec- together. After the froth has subsided, filter onds, depending so much upon the intensity the solution through a clean sponge, two or of the light that it can only be ascertained by three thicknesses of linen, or, still better, filbetter, filexperience, the slide is replaced in the holder tering paper. The solution above named will and the plate taken to the dark room for development. coat more plates than an amateur would be likely to use. Use fresh eggs and a newly made solution whenever coating plates. The plates so prepared will keep indefinitely.