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Opal Glass

gelatine and water

OPAL GLASS is made by fusing one of the oxides of tin or zinc with the metal. It is sold for photographic purposes in two different states, i.e., "plain" and "smoothed," the former possessing the natural polished surface of the glass, and the latter being very finely ground. The latter is more generally employed, owing to the softer effect given to the picture, and also to the difficulty in obtaining even pieces of the polished kind.

Flashed opal is made by laying a thin veneer of the opal glass on to a greater thickness of clear glass.

OPALINE.—This is a name given to prints mounted in optical contact with a piece of clear beveled glass. In this manner they possess somewhat the appearance of a picture upon opal glass. The prints should, if possible, be vignetted, so as to leave a white margin all round the edge of the glass. The method of mounting them in optical contact is the following: After toning, fixing, and washing, the pictures are dried between blotting boards placed under pressure.

Soak about two ounces of soluble gelatine in cold water until soft, then add sufficient boiling water to make a rather thick solution. When the gelatine is thoroughly dissolved, filter it through muslin into a clean glass or porcelain dish standing in a hot water bath, the temperature of the solution to be kept at about ioo deg. F. Have the beveled-edged glasses perfectly clean and near at hand. Immerse a print in the gelatine, and when soaked lift it out and lay it quickly on the glass, and at once firmly squeegee it.

When dry the print is trimmed with a sharp knife to the exact size of the glass on which it is mounted. A piece of leatherette paper can be pasted on to the back to give a better