Kruger.
Ed. Turrell. | ||
|---|---|---|
| Glacial Acetic Acid | 4 | parts. |
| Absolute Alcohol | 1 | part. |
| Nitric Acid (specific gravity, 1.28) | 1 | part. |
The acetic acid and alcohol are mixed and allowed to stand for half an hour, then the nitric acid is added very gradually. This mordant is applied from one to fifteen minutes, according to the strength desired, and may be strengthened by adding nitric acid.
Etching Solution with Alcohol.
Alcohol seems to be added with the object of softening the action in the first biting, and of making the mordant bite at once. For etching Niepce de St. Victor’s asphaltum plates, M. Lemaitre used, for the first biting:
| Nitric acid, at 36° | 1 | part. |
| Distilled Water | 8 | parts. |
| Alcohol, at 36° | 2 | parts. |
And finished off with nitric acid and water, without alcohol.
Etching Solution with Nitrate of Silver. | ||
|---|---|---|
| Alcohol | 6 | parts. |
| Distilled Water | 9 | parts. |
| Pure Nitric Acid | 16.6 | parts. |
| Nitrate of Silver | 0.83 | parts. |
The liquid improves by keeping. Before beginning, wash the plate for a few seconds with dilute nitric acid (at four per cent.), then apply the above mordant for about three minutes, and wash off with distilled water containing six per cent. of alcohol. Repeat the biting as often as may be necessary, well washing between each operation.
Deleschamps.—Glyphogen. | ||
|---|---|---|
| Acetate of Silver | 8 | parts. |
| Rectified Spirits | 500 | parts. |
| Distilled Water | 500 | parts. |
| Pure Nitric Acid | 260 | parts. |
| Nitric Ether | 64 | parts. |
| Oxalic Acid | 4 | parts. |