The American Carbon Manual/Carbon Printing in the Solar Camera
CARBON PRINTING IN THE SOLAR CAMERA.
By Antonio Montagna.
The process I use to make enlarged carbon prints consists of six successive operations:
1st. Choice and Preparation of the Glass.—The glass must be pure white, and the surfaces flat and parallel. After cleaning it in the ordinary manner, I cover it with alcohol 30 grammes, water 8 grammes, and nitric acid 10 drops. I dry it, and throw on the surface a small quantity of dry soap powder, the excess of which I remove by gentle touches of a fine brush.
2d. Coating with Collodion.—My collodion consists of ether 150 grammes, alcohol 80 grammes, and gun cotton 6 grammes, and the glass is covered with it in the usual manner. After drying, I proceed to
3d. Application of the Sensitized Gelatine.—This preparation consists of
|Distilled water,||90 grammes.|
|Pure gelatine,||10 grammes.|
|Bichromate of ammonia,||1.25 grammes.|
|Liquid Indian-ink,||15 grammes.|
To this is added a sufficient quantity of some aniline color; for instance, Magenta, to give a warm tone to the picture.
This preparation is poured over the dry collodion film, and dried in a horizontal position, so that the film attains the same thickness throughout.
4th. Exposure in the Solar Camera.—The printing is done from behind. The side not coated is exposed to the image of the negative, and the time of this exposure is only half as long as that required to obtain a print on chloride of silver paper.
5th. Development.—This is simply done by repeated washings in warm water, and, when the soluble gelatine is removed, washing is continued with cold water; then the glass is dried in an oblique position.
6th. Mounting of the Print and Separation from the Glass.—As soon as dry the print may be retouched, if necessary. This retouching must be done by looking at it by transmitted light. To mount it I paste, by means of gelatine, one or more sheets of white on very light tinted papers or cardboard on the print, taking great care to remove all air-bubbles which may be entrapped between the paper and the moist glue. I place it under pressure, and leave it for twenty-four hours; then I cut the edges loose with a penknife, and leave it exposed to the air; when in a short time the paper spontaneously detaches from the glass, the print adhering firmly to it.
When the paper used has a proper tint in harmony with the subject, and with the carbon and Magenta color of the print, it has all the appearance of a varnished oil painting.
The author liberally offers any more information on the subject to all who desire it.
Note.—Notwithstanding this process is a little laborious, and more adapted for amateur performance than for the regular profession, it contains so many practical hints that it was thought its publication might be of benefit to those who desire large carbon prints.
- The gramme is very near 15 grains, Troy.