THE PHOTOGRAPHIC NEWS. Dec. 3, 1858, p.152
Q. What is the best method of preparing the paper for the waxed paper process'?
A. The best, simplest, and most rapid process of waxing the paper is as follows:--Procure an iron plate, about a quarter of an inch in thickness, and a little larger than the paper to be used; place this plate over a furnace heated with charcoal, and keep it at a regular temperature; upon this plate then place one or two sheets of clean paper, on which arrange your paper for waxing.
Q. What sort of wax should be employed?
A. Either white or yellow wax will answer; but white,, being the purest, is generally used in preference to yellow.
Q. How is the wax to be applied to the paper?
A. A piece of fine white wax is passed to and fro upon it until the surface of the paper is completely impregnated. Another sheet of paper is then laid on and waxed in a similar manner; a third and a fourth, even up to ten, may be added. They must then be separated, and each piece be placed between folds of blotting paper, and an ordinary iron, moderately hot, be passed over them.
Q. Wherein does the necessity exist for the further application?
A. The waxed paper being placed between blotting paper, the additional heat is applied for the purpose of removing any excess of wax which it may have taken, and which is, by this means, absorbed by the blotting paper.
Q. What is the advantage obtained by this waxing process?
A. The chief advantage of the wax in this operation is, not solely that it gives greater force to the picture than by the ordinary process, but that it gives additional transparency to the paper and by impregnating its texture renders the subsequent operations far more complete than would otherwise be the case, and consequently makes the paper retain its sensitive properties for a considerable period.
Q. The paper having been waxed, what is the next operation?
A. A solution is prepared in the following proportions:--Sugar of milk, 620 grains; iodide of potassium, 225 grains; cyanide of potassium, 12 grains; fluoride of potassium, 7 grains, in about a pint and a half of rice water. The cyanide and fluoride of potassium may be substituted by about 45 grains of bromide of potassium.
Q. Will this solution keep for any length of time?
A. It will keep perfectly good for a considerable time.
Q. How is the solution applied to the waxed paper?
A. Some of the solution is poured into a bath or earthenware dish, and the waxed paper is plunged into it sheet by sheet, one over the other, great care being taken to remove any air bubbles which may arise. The sheets may remain in the bath from half an hour to two hours, until they have thoroughly absorbed the solution. The whole mass should then be turned over, and the first sheet removed and hung up to dry. It may easily be attached to a line by means of a pin at one corner; the drop on the lower angle should be removed by touching it with blotting paper.
Q. What is the next operation?
A. The paper, prepared as already stated, may either be employed at once or preserved for future use.
Q. Is it, then, in this state, ready for the camera?
A. No, it has to pass through a third process before it is capable of receiving a photographic impression.
Q. What is the third process?
A. A solution has to be prepared as follows:--Distilled water, 1 pint; crystallised nitrate of silver, 665 grains; crystallised acetic acid, 760 grains.
Q. How is this solution applied to the paper?
A. Three baths of glass or earthenware should be placed near each other. Great care must be taken that these vessels are chemically clean. A portion of the last solution must be filtered into one of these baths; in the other two should be pure distilled water. A packet of thick blotting paper is also required. These preparations being made, take a number of sheets of the waxed paper, and proceed thus:--Take the first sheet, and carefully place it upon the aceto-nitrate bath, taking great care that no air bubbles interpose. Allow it to remain in contact with the fluid until chemical combination is effected.
Q. What is the general time taken to effect this combination?
A. Eight or ten seconds arc sufficient for some kinds of paper, and four or five minutes are required for others. When a violet tint appears the paper should he removed. It must be immediately removed; immersed in the distilled water (No. 1); thoroughly washed, and then removed to distilled water (No. 2); after which it should be dried, or partially dried, by the blotting paper.
Q. Must the sensitive paper be used immediately?
A. When it is desired to keep the paper for same time before using, it is recommended that the application of the nitrate of silver be less than on other occasions. It will thus be seen, that the papers which are prepared for keeping are not those which are the most sensitive; hence it is necessary to expose them for a much longer period to the action of the light than those prepared by a stronger solution of silver.
Q. How is the image taken in the camera developed?
A. By a solution of gallic acid in distilled water, in the following proportions:--Gallic acid, 6 grains; distilled water, 4 ounces; and a few drops of the silver bath. The paper should be immersed in this solution, and allowed to remain in it until the picture is fully developed.
(To be continued.)