Hydroquinone and Eikonogen.—The advantage of combining eikonogen with quinol lies in the fact that one provides what the other lacks, the eikonogen tending to give detail without density and the quinol (in inexperienced hands) giving density without detail. The following formula will be found very satisfactory:—
| A. | ||
| Quinol | 40 | grains. |
| Eikonogen | 120 | " |
| Sodium sulphite | 480 | " |
| Citric acid | 20 | " |
| Water to | 20 | ounces. |
Dissolve the sodium sulphite and citric acid in 15 ounces of water, then add the other ingredients and enough water to make a total bulk of 20 ounces.
| B. | ||
| Sodium carbonate | 60 | grains. |
| Sodium hydrate | 30 | " |
| Potassium bromide | 5 | " |
| Water to | 20 | ounces. |
For use, mix one part of A, one part of B and two parts of water. The same remarks as to over and under-exposure apply as in the case of metol.
Toning Bromide Prints.—The "tone" or colour of the deposit depends largely upon the accuracy of exposure and the developer employed. Ferrous oxalate gives a rich black deposit, but to my mind metol and the combined eiko-quinol give tones at least as beautiful with pretty gray half-tones.
But some people prefer warmer colours, brown and red for instance, and some get brownish blacks (through over-exposure and the use of bromide) which they would like to change.
The colour of the deposit may be changed in various ways by treating the print in baths of different metals. I will give a brief outline of the methods employed, leaving readers to modify them to suit each particular case.
Black and Blue-black Tone.—Brownish black prints can be much improved after fixing by immersion in a strong bath of gold chloride; the following is the strength used by me:—
| A. | ||
| Ammonium sulphocyanide | 20 | grains. |
| Water | 1 | ounce. |
| B. | ||
| Gold chloride | 2 | grains. |
| Water | 1 | ounce. |