THE CARBON PROCESS.
The carbon tissue is seldom prepared by photographers. However, for the sake of completeness, we shall give the formula of the mixtures most generally employed, and describe the manner of coating the paper on a small scale.
Preparation of the Tissue.—The gelatine generally recommended to compound the mixture is the Nelson's autotype gelatine. Coignet's gold label gelatine, mixed with a more soluble product, such as Cox's gelatine, for example, gives also excellent results.
| Gelatine | 110 parts |
| Sugar | 25 parts |
| Soap, dry | 12 parts |
| Water | 350 parts |
The coloring substances consist of:
| FOR ENGRAVING BLACK. |
|---|
| Lamp-black | 20 parts |
| Crimson lake | 2 parts |
| Indigo | 1 part |
| FOR WARM BLACK. |
|---|
| Lamp-black | 3 parts |
| Crimson lake | 3 parts |
| Burnt amber | 2 parts |
| Indigo | 1 part |
| FOR SEPIA |
|---|
| Lamp-black | 2 parts |
| Sepia of Cologne | 18 parts |
| FOR PHOTOGRAPHIC RED BROWN. |
|---|
| India ink | 3 parts |
| Crimson lake | 4 parts |
| Van Dyck brown | 4 parts |