I find the following to serve admirably as a "lubricator: " A. Paraffine, eight drachms; benzine, ten ounce. B. In a mortar grind gum ammoniacum thirty grains, in alcohol suffi-cient to prevent the gum from sticking to the pestle. Add A and B together, shake well, and apply with a flannel rag or sponge. - John r. Clemons.
302. A still higher polish may be given to the print by coating it with a mixture of gelatin. It is questionable whether such a high degree of "shine" is "artistic" or not; and it is an absolute certainty that the gelatin film turns color and gives the prints a faded appearance. Moreover, the surface is easily abraded.
303. The trimming of the photograph should always be neatly and carefully done. The edges should be untorn, and the form or shape should be true. A knife is often used with a glass or metal form, but the little invention of Prof. S. M. Robinson, known as his " trimmer," has almost displaced the knife. These trimmers are made of two forms, the one illustrated by Figure 69 being constructed so as to revolve in a socket, in order to make it follow accurately an oval or round-cornered metal " guide," and the one in Figure 70, known as the "straight cut," is for trimming straight edges, a metal guide being used also with it, or it may be worked outside of a glass shape. The theory of these trimmers is, that instead of cutting they pinch off the surplus paper, thereby giving a nicely-bevelled edge to the print, and they are far superior to the knife or scissors if held and used as indicated by the drawings. The first named gives a small turned or rounded corner to the print, which causes it to adhere more neatly to the mounting card. The " straight cut" trims the corners square. The guides are made of sheet-iron, and are cut true by means of a lathe.
302. This way of mounting photographs may not be quite new. The print for this purpose should be a little darker than usual, and fully toned, and after well washing, put between blotting-paper for a short time, and when surface dry floated on the following solution made warm:
304. One great difficulty in mounting, which should not be overlooked, in the cockling or distorting of the card - board, by the unequal drying out of the moisture imparted to them by the mountant A good preventive is to slightly dampen the cards, and then print and card will dry together, though still,alas! not always equally and in concord. Never pile the prints in dose contact while damp in order to keep them straight They are to become soured, and spots will follow to their ruin.
A gentle heat will dissolve the isinglass and gum; then add one drachm methylated spirit, and filter. Float the damp print upon this, and then lay it carefully on a plate of quite clean, clear glass, say patent plate. Now press out the superfluous mixture with a squeegee (or a piece of Indian-rubber tubing will do for the purpose), beginning at the centre of the print with a gentle scraping motion; then allow it to get thoroughly dry. The print will now have all the brilliancy of prints in water; and much detail will be visible that in the ordinary way would not be seen. - Thomas Gulliver.
804. Take half an ounce of gelatin and cover it with water; leave it to soak for, say, twenty-four hours, in which time it will become thoroughly swollen. Now pour off all the superfluous water, except two or three drachms; place the gelatin with this trace of water in a glue-pot, and put it on the fire. When it is melted, add six ounces of alcohol; that which I use has a specific gravity of .820. A most important point, however, is the mode of mixture; the alcohol must be added a little at a time, stirring steadily with a glass rod, and maintaining a moderately high temperature. By proceeding carefully in this way, perfect mixture is secured; and the solution is then poured into a wide-mouth bottle, corked or stoppered, and set aside for use. This, applied to the print, causes a scarcely appreciable degree of expansion, and no subsequent cockling. Its adhesive qualities are perfect, and the preparation keeps well. To prevent the rigid hardness which characterizes good gelatin, I added from one to two drachms of glycerin to the preparation, which is, I think, an improvement.
To mount in an album without cockling, let the photograph be ironed with a hot iron on the back till it is nice and smooth, then place it under pressure till quite flat. A large book answers the purpose admirably. To prepare for mounting, lay the flattened print face downwards on a smooth board or piece of glass, and upon it place a piece of clean, stiff paper an eighth of an inch less all round than the photograph, upon the exposed edge which rapidly and sparely brush some liquid glue (as little as possible) to cover it, for herein lies the great secret. Avoid making the paper wet The album being conveniently placed - the position the photograph is to occupy being previously marked with a pencil - carefully raise the photograph with a point of some kind to avoid soiling the finger with the glued edge, making it non - adhesivo in the parts where such glue would be removed, and lay it down in the proper place. At once lay a piece of clean paper over it, and rub it down firmly with a soft rag; close the book. In half an hour the face will be dry, and the print perfectly flat, and it will remain so. - John L. Gihon.