The American Carbon Manual/Practical Notes on the Carbon Process
PRACTICAL NOTES ON THE CARBON PROCESS.
TRANSFERRING WITHOUT A PRESS—TRANSFERRING WITHOUT GELATINE—CARBON PRINTS ON PORCELAIN GLASS—CARBON NEGATIVES.
Another and very interesting method of transferring prints has been tried practically, after an idea of Mr. Swan, by Dr. Vogel. The characteristic of this method is, that a press can be dispensed with.
The picture, resting on caoutchouc, is immersed in a warm solution of gelatine.
| Gelatine, | 6 to 8 parts. |
| Glycerine, | 2 to 2½ parts. |
| Water, | 100 parts. |
As soon as all the air-bubbles have been removed, a piece of fine paper is immersed, and both the paper and the picture are removed from the dish by drawing them over the corner of the same; both are suspended and left to dry; they can then be easily trimmed, pressed on moist pasteboard, and separated by means of benzine.
Dr. Vogel has recently made the curious discovery also that carbon prints can be transferred without the use of gelatine. This process is much more simple than Swan's. The time which is gained by doing away with gelatinizing, drying, etc, etc., cannot be too highly estimated.
The operation is carried out in the Royal Academy at Berlin, in the following manner:
Common paper, as white and smooth as possible, is dipped for two minutes in cold water; it is then dried a little between blotting-paper, and the developed picture, after having been dried, is laid on it, picture side down, and smoothed over with the hand. After this, it is placed in the press, the moist sheet downwards, and on it a piece of felt. It is drawn once through the press, and suspended for drying. The rollers must work very evenly, or the pictures are apt to become wrinkled.
For small pictures, a copying press will suffice. The moist paper is placed upon blotting-paper, the picture is placed on top of this, it is pressed down a little with the hand, and then pressed in the press for about two minutes.
After drying for thirty minutes, the picture is dipped for one minute into a solution of chromate of alum, 1:300. After this, it is dried again. The time required for drying at 16° Beaume, is about one hour. The separation is performed as described above. The benzine is applied on the side of the caoutchouc paper.
The conditions for the success of this process are: a soft caoutchouc paper, a good caoutchouc solution, well-sized paper, and strong pressure.
Careful drying is important, and strong rubbing in with benzine. If, however, in separating, some parts of the picture should tear, and the whole picture should be difficult to separate, then it is better to stop the separation at once, to place the picture into a glass or tin dish, to place a piece of plate-glass upon the picture in order to press it, and to pour benzine upon them until they are covered.
To avoid the evaporation of the benzine, place the dish with the pictures into a larger dish, which fill for about one-quarter of an inch with water, and now place over the dish containing the pictures, another one inverted, which will dip with its sides in the water, and prevent evaporation. The pictures remain in this for about ten minutes, when they can be easily separated.
All pictures must, on account of the caoutchouc which attaches itself to them, be rubbed off with a piece of flannel saturated with benzine.
When the picture on caoutchouc has been thickly gelatinized (12 per cent, gelatine), it will be easy to remove it from the paper as a pure film.
This circumstance led me to experiment, to transfer the carbon (pigment) picture to glass, and the experiment succeeded perfectly. For this purpose, I covered the picture resting on the caoutchouc, thickly with a solution of gelatine:
| Gelatine, | 12 parts. |
| Glycerine, | 4 parts. |
| Water, | 100 parts. |
And I glued it in this manner to a previously-warmed plate of glass, avoiding, of course, all air-bubbles. After having left it for drying, I removed the paper with benzine, and the picture remained perfect on the glass.
It is advantageous to cover the paper on the back, after drying, with a solution of—
| Chromate of Alum, | 1 part. |
| Water, | 300 parts. |
Dissolve off, as usual, with benzine. Should there be any difficulty in removing the picture, it is advisable to place it in benzine in the manner described above.
The transfer to porcelain (opal glass), is performed in the same manner. This gives very pretty effects, but great care must be exercised in dissolving them off.
It is self-evident, that this process is of great importance for the email and porcelain photographs.
If, to the pigment of the first gelatine sheet, an email color has been mixed, a picture will be obtained which can be burnt in.
Another interesting circumstance, I only wish to indicate. In the pictures on glass, we evidently have a carbon (pigment) positive. From this, it will be easy, by repeating the process, to produce a carbon negative.
We would thus be enabled to multiply our negatives, and to produce, instead of the perishable silver negatives, permanent ones by the carbon or pigment process.