MAGIC PHOTOGRAPHS.—A process for making these was first pointed out by Sir John Herschel. Prints on albumenized paper were first made and fixed without any toning. They are then washed thoroughly and immersed in a saturated solution of perchloride of mer cury. The action of this solution is to bleach the image until it becomes of the same color as its paper support.
It then becomes invisible, and is washed and dried. By simply laying a piece of dampened blotting paper, previously soaked in a saturated solution of hyposulphite of soda, the image will instantly re-appear, far brighter than before. It can then be washed, and a fairly permanent image obtained. These invisible images may also be developed by ammonia or by tobacco smoke. Some years ago a little novelty was brought out in Paris. It con sisted of a cigar or cigarette tube (see Fig. 273), having a hollow chamber, through which the smoke passed. Small pieces of paper, on which were invisible images, manufactured as above, were then placed in the smoke chamber, and after smoking a cigar or cigarette, the picture, fully developed, was removed. Owing to the nature of many of these Parisian studies, however, many of them were better had they remained in the latent state.
rtmalc VIGNETTE.—These are reversed vignettes, that is to say the margins round the portrait instead of being white as in the ordinary vignette are black. A method of making them was recently described by " Teinte " in The Photogram. This was as follows : Two methods can be adopted. The first of these about to be detailed, though entailing, perhaps, in the first place a trifle more trouble, produces the best results. We require a black background, preferably of black velveteen, large enough for a head and shoulders. As the material is not usually obtainable of a width greater than twenty inches or so, there will have to be a seam, and this must be very neatly done. The seamed velveteen is then stretched taut on a frame, which should preferably be covered first with calico, to prevent " sagging." Always, before use, dust the velveteen with a soft brush—say, a hat brush—to remove any adhering dust or fluff. Instead of velveteen, a good paper background can be used. only it must be seen that the smooth clirfan. i-trl f rnrr, n,nnl r pe n.nocso ntIrl ;e 4. ee LAS ,11:16,... 4J1 G11.1.14 1.0 dead black.
We require also a vignetting mask suitable to the subject, with a serrated edge. This has to be fixed inside the camera between the lens and plate.* The proper posi tion can be found by trial ; the further the card is away from the petal the softer and more gradual the vignetting.
No special arrangement for holding this is required beyond what can be prepared by any one who can use his fingers. We take a piece of stout card, the outside of which will just fit into the folds of the camera's bellows, and by a little twisting it can be sprung in between the folds and will hold them. There is an opening in the center, square in shape, about quarter plate size. This acts as a frame to hold the vignetting mask which has the opening of proper size and shape. By using a frame as described the vignetter can be moved about up and down and from side to side, and when . . .
the correct position is fixed by drawing pins. The frame and vignetter should be blacked all over. For this purpose take some lampblack ground in turps, and mix with it a little gold size sufficient (found by trial) to prevent the lampblack from rubbing off when dry, but not enough to cause the paint to dry shiny.
A good distance to fix the vignetter is about one-third the extension of the camera when the object is in focus, measuring from the lens.
We adjust the camera so that the image of the figure falls in the correct position on the screen, and the vignette is made of such a size and shape as to give the amount required.
The shadow of the mask protects the edges of the plate surrounding the image, and in development we obtain a negative in which the image is vignetted into clear glass, and on print ing from such the margins print dark. The printing of such a negative should be prolonged until the margins of the picture are quite lost, or they are apt to show after toning.
The sketch shows the arrangement of vignetter inside camera.
The other plan consists in making an ordinary negative, using preferably a dark back ground. From this is made a vignette in the ordinary manner. When this comes from the frame it is placed on a piece of clean glass—face up—and another piece of glass free from flaws placed over it. Now cut a piece of card to the size and shape of the vignetted portion of the print, and fix this with glue to a piece of cork. This piece of cork must vary in thickness with various pictures. Now place the cork on the glass so that the mask covers the picture and fix with glue to prevent slipping. Place the whole out in diffused light, and allow the darkening of the margins to go on until sufficiently deep. The print is then toned.
The height of the card from the print must be such that no abrupt line is produced between the first printing and the darkened margin, but that one will shade into the other without break.