MOUNTING PRINTS. This consists in attaching the print, either entirely, or by its edges, to a sheet of cardboard, by means of an adhesive cement.
Of all adhesive substances, starch appears to be the most suitable. It should not be made too thick, and after being boiled should be strained through a cloth, and used quite fresh, as sour starch would be certain to cause the fading of the print.
The face of the cardboard is first damped with a moist sponge, to cause it to expand in the same degree as the print when the starch is applied to it. If this be not done, the print contracts on drying, and draws the cardboard out of shape. The print is then laid with its face upon a slab of glass, and the starch spread thinly and evenly upon the back with a stout hog-hair paint-brush. The print is then applied carefully to the damp cardboard, and lightly pressed into Contact, and air bubbles pressed out, with a linen rag. A sheet of cardboard is then laid upon it, and the rag rubbed over this pretty forcibly in order to ensure the perfect adhesion of the print to the mount in every part. The cardboard upon which the print is mounted
is then pinned up by one corner to dry, and afterwards placed under a book-binder's press, or a board loaded with weights.
French cardboard is mechanically the best for the purpose, and the thicker it is the easier the operation becomes ; but the bluish tint of French cardboard is very objectionable, as it contrasts disagreeably with the tint of most photographs. Cream colour is far better ; and there is no doubt that cardboards might be manufactured of a great variety of suitable tints, and that the general effect of photogra phic prints would be greatly improved by being mounted upon such. Stereoscopic subjects should be mounted upon cardboards nearly if not absolutely black ; and collodion positives on paper either upon gilt or deep purple cardboard. As a general rule a photograph should never be contrasted with anything absolutely white, or what is even worse, of a bluish white like French paper.