PHOTOGRAPHS ON VARIOUS FABRICS.
By means of a dye process known as the "Primuline Process," very pretty images in various colored dyes can be made upon silks, satins, cotton goods, etc. The material is first dyed in a hot solution of primuline, made by adding about 15 to 30 grains of the dye to a gallon of hot water; a little common salt should also be added. On immersing the fabric, and stirring it about in the solution, it becomes of a primrose yellow color, when it is removed and washed under a cold-water tap. The next process is to diazotize it by immersion for half a minute or so in a cold solution of sodium nitrate, one-quarter per cent., which has been sharply acidified with hydrochloric or other acid. The material is again washed in cold water, but it must be kept in a weak light. It can be hung up to dry, in the dark, or exposed while wet beneath the object of which it is required to produce a positive reproduction. This process gives a positive from a positive, so that any ordinary picture on a sufficiently translucent material--flowers, ferns, etc.--can be reproduced. Printing requires about half a minute in the direct sunlight to half an hour or more in dull weather, or if the material to be printed through is not very transparent. The high lights become of a pale yellow, so that a faint image is perceptible; but this is made visible in almost any color by development in a weak solution (about one-fourth per cent.) of a suitable phenol or amine. The following have been found suitable:
_For Red._--An alkaline solution of [Greek: b]-napthol.
_For Maroon._--An alkaline solution of [Greek: b]-napthol-disulphonic acid.
_For Yellow._--An alkaline solution of phenol.
_For Orange._--An alkaline solution of resorcin.
_Brown._--A slightly alkaline solution of pyrogallol, or a solution of phenylene-diamine-hydrochloride.
_For Purple._--A solution of [Greek: a]-napthylamine hydrochloride.
_For Blue._--A slightly acid solution of amido-[Greek: b]-napthol-sulphonate of sodium, now better known as "eikonogen."
If the design is to be made in several colors, this can be done by painting on the different developers, suitably thickened with starch.
After developing, the material is well washed and dried. With the purple and blue developers it is necessary to wash the material finally in a weak solution of tartaric acid. Wool and silk require a longer exposure to light than other fabrics, and cannot be successfully developed with the maroon or blue developer.
SILHOUETTES
[Ill.u.s.tration: AA. The sky and side light. BB. Two dark backgrounds.
C. The white screen in oblique position. D. The subject. E. The camera. FIG. 30.]
[Ill.u.s.tration: FIG. 31.]
Silhouette portraits were at one time very popular. They are simply made, and if the effect is well carried out will afford considerable amus.e.m.e.nt. The best description of their manufacture was given some time ago by Herr E. Sturmann, in _Die Photographische Korrespondenz_.
His method is as follows:
Place two dark backgrounds in parallel position about 4 feet from the sky and side light of the studio and distant from each other about six feet. Improvise a dark tunnel by drawing a black cloth, of non-reflecting material, over the two dark grounds, and arrange a white screen, somewhat larger than the distance between the two dark grounds, in an oblique position so as to be fully illuminated.
The subject to be silhouetted must be placed in the centre of the tunnel, one side of the face turned towards one ground, but comparatively nearer to the white screen so that the side of the face turned towards the camera is as much as possible in the shade.
[Ill.u.s.tration: FIG. 32.]
Focus must be taken accurately, so that the outlines of the figure are perfectly sharp.
As it is the object to obtain a perfectly transparent, gla.s.s-clear silhouette upon an absolutely opaque ground, but a very short time of exposure is required.
Develop as usual and to secure perfect opacity intensify more than usual. Plates of lower sensitiveness invariably give the best results.
A slow plate or one made particularly for reproduction is well adapted for this kind of work. With ferrous oxalate or hydrochinon developer there is scarcely any need of intensifying.
[Ill.u.s.tration: FIG. 33.]
[Ill.u.s.tration: FIG. 34.]
To obviate the shadows cast upon the floor by the lower parts of the figure, place it upon a thick, large plate-gla.s.s, supported by props of five or six inches in height, and spread upon the floor under the gla.s.s a piece of white muslin. The muslin must be free of folds or wrinkles, and be so connected with the white screen, that the division line between is not reproduced upon the plate.
The very feeble shadows of the feet can be easily touched away with pencil.
Single persons or groups of two or three figures can be photographed in this peculiar style with very good effect.
For heads and busts expose in the usual manner, but to obtain silhouettes similar to those our grandmothers had cut in black paper, and long before photography was thought of, cut an appropriate mask of black paper to cover the part not wanted during printing.
[Ill.u.s.tration: FIG. 35.]
It should be borne in mind that in this cla.s.s of work the white background only is the object to be photographed, hence the necessity of but very short exposures. With longer exposures absolute blacks and whites are impossible.
PHOTOGRAPHING THE INVISIBLE.
The following is a curious and interesting experiment, based upon the peculiar property possessed by fluorescent substances of altering the refrangibility of the chemical light rays. Take a colorless solution of bisulphate of quinine, and write or draw with it on a piece of white paper. When dry the writing or design will be invisible, but a photograph made of it will show them very nearly black.
HOW TO MAKE A PHOTOGRAPH INSIDE A BOTTLE.
Get a gla.s.s-blower to make an ordinary shaped wine-bottle of very thin and clear gla.s.s, and clean it well. Next take the white of two eggs and add to it 29 grains of ammonium chloride dissolved in 1 drachm of spirits of wine, and one-half ounce of water. Beat this mixture into a thick froth and then allow it to stand and settle. Filter through a tuft of cotton-wool, and pour into the specially made bottle. By twisting the bottle round, an even layer of the solution will deposit itself on the sides. Pour off the remaining solution, allow the film in the bottle to dry, and again repeat the operation.
The next operation is to sensitize the film with a solution of nitrate of silver, 40 grains to 1 ounce of water. Pour this in and turn the bottle round for a few minutes, then pour off the superfluous solution and again dry. Hold the neck of the bottle for a few seconds over another bottle containing ammonia, so as to allow the fumes to enter it. Printing is the next operation; this is accomplished by tying a film negative round the bottle, and covering up all the other parts from the light. Print very deeply, keeping the bottle turning round all the time. Toning, fixing, and washing can be done in the ordinary way by filling the bottle up with the different solutions. The effect is very curious, and can be improved by coating the inside of the bottle with white enamel.
PHOTOGRAPHS IN ANY COLOR.
These can be produced by what is known as the powder or dusting-on process. The principle of the process is this: An organic, tacky substance is sensitized with pota.s.sium bichromate, and exposed under a reversed positive to the action of light. All the parts acted upon become hard, the stickiness disappearing according to the strength of the light action, while those parts protected by the darker parts of the positive retain their adhesiveness. If a colored powder be dusted over, it will be understood that it will adhere to the sticky parts only, forming a complete reproduction of the positive printed form.
Prepare--Dextrine, one-half ounce; grape sugar, one-half ounce; bichromate of potash, one-half ounce; water, one-half pint: or saturated solution bichromate of ammonia, 5 drachms; honey, 3 drachms; alb.u.men, 3 drachms; distilled water, 20 to 30 drachms.
Filter, and coat clean gla.s.s plates with this solution, and dry with a gentle heat over a spirit lamp. While still warm the plate is exposed under a positive transparency for from two to five minutes in sunlight, or from ten to twenty minutes in diffused light. On removing from the printing frame, the plate is laid for a few minutes in the dark in a damp place to absorb a little moisture. The next process is the dusting on. For a black image Siberian graphite is used, spread over with a soft flat brush. Any colored powder can be used, giving images in different colors. When fully developed the excess of powder is dusted off and the film coated with collodion. It is then well washed to remove the bichromate salt. The film can, if desired, be detached and transferred to ivory, wood, or any other support.
If a black support be used, a ferrotype plate on j.a.panned wood, for instance, pictures can be made from a negative, but in this case a light colored powder must be used. The j.a.panese have lately succeeded in making some very beautiful pictures in this manner. Wood is coated over with that black enamel for which they are so famous, and pictures made upon it in this manner. They use a gold or silver powder.
With this process an almost endless variety of effects can be obtained. For instance, luminous powder can be employed and an image produced which is visible in the dark.
Some time ago we suggested a plan of making what might be termed "post-mortem" photographs of cremated friends and relations. A plate is prepared from a negative of the dead person in the manner described, and the ashes dusted over. They will adhere to the parts unexposed to light, and a portrait is obtained composed entirely of the person it represents, or rather what is left of him. The idea is not particularly a brilliant one, nor do we desire to claim any credit for it, but we give it here for the benefit of those morbid individuals who delight in sensationalism, and who purchase and treasure up pieces of the rope used by the hangman.