Until improvements in photo-mechanical printing methods enable us to economically and conveniently impress the photographic image directly upon cardboard, the work of mounting prints will form a considerable item in the labour account of the photographer; as the public look with but little favour upon an unmounted picture, the number sold is comparatively small. A mounted photograph is seldom so flat and even as the original card, because the albumenised paper, expanded by the moisture of the adhesive material used, contracts in drying, and distorts the card mount; this distortion being generally so considerable, that in the case of a print mounted upon a large card, a decided concavity of the picture results, while a small card nearly covered by the photograph is generally drawn either into a gutter or a bow-like form. These disadvantages can be readily overcome by adopting the simple and easy expedient of gumming the prints, allowing them to dry, and then causing them to adhere to slightly damped mounts by the application of considerable pressure.
The work of gumming the back of the photographs can be very quickly performed if a broad brush is used, but as the gumming of paper is now a distinct trade in London, it is more advantageous to send them to be gummed, more especially when the sheets are printed upon whole. A ream of paper, the same size as the ordinary sheets used for photographic purposes (17 1/2 by 21 1/2), can be gummed in London for about 10s., this sum including the gum. The gummed pictures are next trimmed in the usual way, when all is ready for the work of mounting.
A card is very lightly damped on the face with a sponge, the gummed photograph is placed in position, and the whole is quickly run through a lithographic or a roller press. Far less moisture is required than might be supposed, as the pressure brings to the surface that water which has soaked into the card, and the mounted photograph, when taken from the press, is, to all appearance, as dry as if it had not been damped at all; and, what is more important, it has no tendency to curl. A smooth lithographic stone forms the best basis upon which to lay the print when the pressure is applied, and a sheet of smooth card or glaze board should be laid over the picture before the leather tympan is closed down upon it. Assuming the pictures to be already gummed, about 400 per hour can be mounted by this method, and it must be remembered that the effect of the pressure is almost equivalent to rolling. The method referred to has long been in use by collotype printers, in this country and abroad, for mounting their pictures.
A small lithographic or autographic press, suitable for work up to about 12 by 10, can be obtained for a very moderate sum. (Photo. News.)