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Paper Prints (Albuminized Paper)

Albuminized Paper.

Formula 1.-Take of chloride of ammonium, 200 grs.; water 5 oz.; albumen, 15 oz.

Chloride of barium is sometimes used in salting paper, instead of chloride of ammonium, but is contraindicated when the alkaline gold-toning process is adopted, since the carbonate of soda would throw down carbonate of baryta in the paper.

When pure albumen is used without water, from 5 to 8 grs. of salt to each ounce will be sufficient. The less the quantity of salt the warmer the color, but it must not be so far reduced as to injure the contrast and depth of shadow in the print.

If distilled water cannot be procured, rain-water, or even common spring-water, will often answer the purpose. For the albumen use eggs nearly fresh, and be careful that in opening the shell the yolk be not broken. Each egg will yield about one fluidounce of albumen.

When the ingredients are mixed, take a bundle of quills or a fork, and beat the whole into a perfect froth. As the froth forms it is to be skimmed off and placed in a flat dish to subside. The success of the operation depends very much upon this part of the process, for, if the albumen be not thoroughly beaten, flakes of animal membrane will be left in the liquid, and will cause streaks upon the paper. When the froth has partially subsided transfer the liquid part to a tall and narrow jar, and allow to stand for several hours, that the membranous shreds may settle to the bottom; then pour off the upper clear portion, which will be fit for use. Albuminous liquids are too glutinous to run well through a paper filter, and are better cleared by subsidence. Lower the paper on the liquid by one steady movement, since, if a pause be made, a line will 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 oxgall sold by the artists' colormen, 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.

To render the Paper Sensitive.

This operation must be conducted by the light of a candle or by yellow light.

Take of nitrate of silver, 60 grs.; distilled water, 1 oz. Prepare a sufficient quantity of this solution, and pour it out into a porcelain dish. After it has been a short time in use, the albumen, dissolved out of the papers, will cause a greasy scum to form upon the liquid, which, if allowod to remain, produces marble stains upon the sensitive paper; it must therefore be removed by folding a strip of blotting-paper the exact breadth of the dish, and drawing it lightly along the surface; lay the sheet upon the solution in the same manner as above described for the albumen. Three. minutes' contact will be sufficient with thin paper, but if a thick paper be used 4 or 5 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 to be held by the finger and thumb, and allowed to drain a little before again putting in the pin, otherwise a 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.

Formula 2.-Preparation of Plain Paper.

Take of chloride of ammonium, 200 grs.; citrate of soda, 200 grs.; gelatine, 20 grs.; water, 20 oz.

To prepare the citrate of soda dissolve 112 grs. of citric acid in 20 oz. of water, and add 133 grs. of the dried bicarbonate or sesquicarbonate of soda used for effervescing draughts. Supposing the citric acid to be adulterated with tartaric acid, the above quantity of carbonate of soda would be too great, and free alkaline carbonate would then remain in the liquid after the neutralization was complete. The size of the paper would be liable to suffer in such a case, and the print would not be clean and bright. Excess of citric acid, on the other hand, gives very clean pictures, but they are too pale and red, without depth of shadow. Amateurs, desirous of simplifying the formula, may substitute an equal weight of "Rochelle salt" for the citrate of soda. This substance is a tartrate of potash and soda, and is sold by druggists in large crystals. Both tartrates and citrates are used for the purpose of giving a red and warm tone to the prints.

Render sensitive by floating for 2 or 3 minutes upon the solution of nitrate of silver employed for the albuminized paper.

Formula 3.-Ammonio-Nitrate Paper.

This is always prepared without albumen, which is dissolved by ammonio-nitrate of silver, Take of chloride of ammonium, 40 grs.; gelatine, 20 grs.; water, 20 oz. Dissolve by the aid of heat, and filter when cold.

Take 10 or 12 sheets of thin Saxe paper, and, having marked the right side, immerse them bodily in the liquid, 1 by 1, with care to remove air-bubbles; then turn the batch over, and remove them singly, beginning with the sheet first immersed.

Each paper will thus be a similar length of time in the salting liquid.

This salting solution is very weak, but it must be borne in mind that the papers being immersed will take up a large quantity, and also that the ammonio-nitrate process requires less salt, inasmuch as the silver solution is to be laid on with a brush.

An ammonio-nitrate paper, yielding a very rich color, is made by salting Towgood's paper, or Papier Saxe, with a mixed chloride and citrate, in quantity exactly one-half of that advised in the last page, and afterwards sensitizing it with an 80 gr. solution of ammonio-nitrate.

Render sensitive by a solution of ammonio-nitrate of silver, 60 grs. to the oz. of water, prepared as follows: Dissolve the nitrate of silver in onehalf of the total quantity of water; then take a pure solution of ammonia and drop it in carefully, stirring meanwhile with a glass rod. A brown precipitate of oxide of silver first forms, but on the addition of more ammonia it is redissolved. When the liquid appears to be clearing up, add the ammonia very cautiously, so as not to incur an excess. In order still further to secure the absence of free ammonia it is usual to direct that, when the liquid becomes perfectly clear, a drop or two of solution of nitrate of silver should be added until a slight turbidity is again produced. Lastly, dilute with water to the proper bulk. If the crystals of nitrate of silver employed contain a large excess of free nitric acid no precipitate will be formed on the first addition of ammonia; the free nitric acid, producing nitrate of ammonia with the alkali, keeps the oxide of silver in solution. From the presence of nitrate of ammonia, it is often useless to attempt to convert an old nitrate bath, already used for sensitizing, into ammonio-nitrate. Or, dissolve 60 grs. of nitrate of silver in oz. of water, and drop in ammonia until the precipitated oxide of silver is exactly redissolved; then divide this solution of ammonio-nitrate of silver into 2 equal parts, to one of which add nitric acid cautiously, until a piece of immersed litmus-paper is reddened by an excess of the acid; them mix from the milky deposit of chloride or carbonate of the two together, fill up to 1 oz. of water, and filter silver, if any be formed.

Ammonio-nitrate of silver should be kept in a dark place, being more prone to reduction than the nitrate of silver.

To Apply the Liquid.

It is not usual to float the paper when the ammonio-nitrate of silver is used. Brushes are manufactured expressly for applying silver solutions, but the hair is soon destroyed unless the brush is kept scrupulously clean. Lay the salted sheet upon blotting-paper, and wet it thoroughly by drawing the brush first lengthwise and then across. Allow it to remain flat for a minute or so, in order that a sufficient quantity of the solution may be absorbed (you will see when it is evenly wet by looking along the surface), and then pin up by the corner in the usual way. If, on drying, white lines appear at the points last touched by the brush, it is probable that the paper was too highly salted, or that the ammonio-nitrate contained free ammonia. Ammonio-nitrate paper is more prone to spentaneous decomposition than either albuminized or plain paper; hence it cannot be kept many hours after sensitizing without turning yellow.

Toning Bath.

No. 1. Solution of chloride of gold, 1 dr.; sesquicarbonate of soda, 10 grs.; distilled water, 6 oz. No. 2. Solution of chloride of gold, 1 dr.; م