The principal difficulty in Albuminizing paper, is to avoid the occurrence of streaky lines, which, when the paper is rendered sensitive, bronze strongly under the influence of the light. To avoid them, use the eggs quite fresh, and lower the paper on to the liquid by one steady movement; if a pause be made, a line will probably be formed. Some papers are not readily wetted by the Albumen, and when such is the case, a few drops of spirituous solution of bile, or a fragment of the prepared Ox-Gall sold by the artists' colour-men, will be found a useful adjunct. Care must be taken however not to add an excess, or the Albumen will be rendered too fluid, and will sink into the paper, leaving no gloss.
In salting and albuminizing Photographic paper by the formula above given, it is found that each quarter-sheet, measuring eleven inches by nine inches, removes one fluid drachm and a half from the bath, equivalent to about one grain and three-quarters of salt (including droppings). In salting plain paper, each quarter-sheet takes up only one drachm; so that the glutinous nature of the Albumen causes a third part more of salt to be retained by the paper.
English papers are not good for albuminizing; they do not take the Albumen properly, and curl up when laid upon the liquid: the process of toning the prints is also slow and tedious. The thin negative paper of Canson, the Papier Rive, and Papier Saxe, have succeeded with the writer better than Canson's Positive paper, which is often recommended; they have a finer texture, and give more smoothness of grain.
To apply the Albumen, pour a portion of the solution into a flat dish to the depth of half an inch. Then, having previously cut the paper to the proper size, take a sheet by the two corners, bend it into a curved form, convexity downwards, and lay it upon the Albumen, the centre part first touching the liquid, and the corners being lowered gradually. In this way all bubbles of air wall be pushed forwards and excluded. One side only of the paper is wetted: the other remains dry. Allow the sheet to rest upon the solution for one minute and a half, and then raise it off, and pin it up by two corners. If any circular spots, free from Albumen, are seen, caused by bubbles of air, replace the sheet for the same length of time as at first.
The paper must not be allowed to remain upon the salting Bath much longer than the time specified, because the solution of Albumen being alkaline (as is shown by the strong smell of Ammonia evolved on the addition of the Chloride of Ammonium) tends to remove the size from the paper and to sink in too deeply; thus losing its surface gloss.
Albuminized paper will keep a long time in a dry place. Some have recommended to press it with a heated iron, in order to coagulate the layer of Albumen upon the surface; but this precaution is unnecessary, since the coagulation is perfectly effected by the Nitrate of Silver used in the sensitizing; and it is doubtful whether a layer of dry Albumen would admit of coagulation by the simple application of a heated iron.
To render the paper sensitive.—This operation must be conducted by the light of a candle, or by yellow light. Take of
| Fused Nitrate of Silver | 60 | grains. |
| Glacial Acetic Acid | 1/3 | minim. |
| Distilled Water | 1 | ounce. |
Prepare a sufficient quantity of this solution, and lay the sheet upon it in the same manner as before. Three minutes' contact will be sufficient with the thin Negative paper, but if the Canson Positive paper be used, four or five minutes must be allowed for the decomposition. The papers are raised from the solution by a pair of bone forceps or common tweezers tipped with sealing-wax; or a pin may be used to lift up the corner, which is then taken by the finger and thumb and allowed to drain a little before again putting in the pin, otherwise a white mark will be produced upon the paper, from decomposition of the Nitrate of Silver. When the sheet is hung up, a small strip of blotting-paper suspended from the lower edge of the paper will serve to drain off the last drop of liquid.
A Bath prepared by the above formula is stronger than is really necessary. Forty grains of Nitrate to the ounce of water is abundantly sufficient if the sample be pure; but it must be borne in mind that the strength of the Bath diminishes rapidly by use, and hence, when the prints begin to be wanting in vigour, with pale shadows and perhaps a spotted appearance, an addition of Nitrate of Silver must be made. Fused Nitrate of Silver is recommended in preference to the crystallized Nitrate, on account of the latter being occasionally contaminated with an impurity alluded to at [page 101]. This when present will be likely to redden the pictures and to interfere with the rapidity of bronzing.