Albert Levy Cyanotipes-. Les Constructions nouvelles. 50 photographies ,The Philadelphia Photographer Vol XVI October 1879 nº 190 PRINTING IN BLUE.
PRINTING IN BLUE.
A NUMBER of inquiries have come to us lately for the process of printing in blue. We have repeatedly given this process, but it has recently been published more in detail in the Franklin Institute Journal, by Mr. David Townsend, of this city, and we reprint from his valuable paper what follows these remarks. Mr. Albert Levy, of New York, Mr. T.H. McCollin, of this city, and in fact all dealers, we believe, supply the paper already sensitized, and for experiment, perhaps, that is the best way to get it. " The process which is most used in America, and which has been largely adopted by our manufacturers, is known as the blue process. The drawings are reproduced in white lines on a blue ground, and I understand the paper is sold in the market already sensitized, although it can be prepared cheaper and just as well as the bought article. Almost any heavy well-glazed printing paper will answer the purpose, but, as this is the only expense, a good quality should be used.
The sensitizing bath consists of
«. Citrate of Iron Ammonia, . 1 part.
Clear Water, . . .4 parts.
b. Red Prussiate of Potash, . 1 part.
Water, .... 6 parts.
"The two solutions are dissolved separately, and preferably at the ordinary temperature ; when in complete solution they are mixed, and kept in a yellow bottle, or carefully excluded from the light, which would cause a blue precipitate. If the paper is not sufficiently sized, gum or gelatin should be added to give it body and prevent the liquid from soaking through. The sensitizing is performed as follows, in non-actinic light : The sheet of paper, cut to therequired size, is pinned to a clean board ;some of the solution is poured into a vessel,and the paper painted with it by means of a soft camel's-hair brush three inches wide. The brush is dipped into the solution and the paper completely moistened in one direction ; then, without removing the liquid,it is smoothed until no streaks or lines appear. Some prefer to use a sponge, but this causes uneven spots, and mars the beauty of the picture. In this way a very little solution will cover quite a large surface. Before putting the brush away it must be carefully cleaned. The paper is unpinned, hung upon a line, and when dry will keep a long timein the dark. It should be a brass-yellow
THE PHILADELPHIA PHOTOGRAPHER 111
into the printing frame, as usual, with a sensitive sheet, and exposed to sunlight for six to ten minutes, or to diffused light for one to two hours. The double salt is reduced to the ferrous state where the light strikes it, and immediately combines with the red prussiate present to form Turnbull's blue, while the protected parts remain unchanged.
The exposure should be continued, until, on opening the frame, the white lines have almost disappeared and the background is grayish-green. The sheet may also be exposed on a board padded with flannel, over which is placed a sheet of plate-glass, but this requires to be always horizontal, and needs more apparatus than it would cost to get a regular frame. When exposure is finished the print is removed, and put immediately into a tank of running water, when the lines will become white (unless overexposed or not in contact), while the groundbecomes dark blue. After sufficient washing,the ground can be improved by transferringto a bath of
Hydrochloric Acid, 5 parts,
Water, . 100 parts
when it must be again thoroughly washed,and then dried. The color always darkens on drying, and prints that would otherwise be underexposed have very beautiful light- blue ground.
"This process has become the favorite one,owing to its great simplicity, and the ease with which any one can work it ; the objections to it are : the length of exposure, especially on cloudy days, and the impossibility of copying drawings from anything but tracing cloth or paper. In very large sheets the fine lines are apt to be reduced, thus making the picture somewhat uncertain in parts. If, instead of mixing the solutions, the paper had been sensitized with the citrate bath and then exposed, the reduction would have been very rapid (fifteen or thirty seconds), as this is the most sensitive salt of iron. The picture could then be developed in the ferricyanide bath, and finished as described ; but in this case it is better to sacrifice sensitiveness to convenience. The other double salts could be used to replace the citrate, but they require a longer exposure.
LÉVY, Albert. ~ English Sea Side Cottages photographed by Albert Levy at Hastings, Margate, Birchington, etc. [Paris], 1902.
Is other photo album of cyanotipes
