This Uranium toner produces brown to red tones.
When toning in uranium a considerable intensification of the the image is effected. Allowance must therefore be made for this increase in density when making a print, which should be rather thin and flat if the best and most vigorous results are required with this bath. Overtoning causes the black to deteriorate. A weak sodium carbonate solution will remove color and image. Wash in acified water.
Stock Solution A
| Chemical | Amount | Units |
|---|---|---|
| Water | 500 | ml |
| Uranium Nitrate | 3.5 | g |
| Acetic Acid | 31 | ml |
| Water to make | 625 | ml |
Stock Solution B
| Chemical | Amount | Units |
|---|---|---|
| Water | 500 | ml |
| Potassium Ferricyanide | 50 | gr |
| Acetic Acid | 31 | ml |
| Water to make | 625 | ml |
USAGE
The toning bath is made in two solutions, which keep indefinitely, and are mixed in equal proportions just previous to use. The mixed solutions to not keep, and must be used as soon as prepared. The prints may be toned in this directly they are taken from the last wash water. If they have been allowed to dry, they should be soaked in water until limp before toning. The toning solution must be kept in motion over the prints to prevent uneven markings, and colours from warm sepia to Bartolozzi red are produced with the greatest ease. When the desired colour is attained, the prints are transferred to a dish of acid water (20 drops acetic acid to a pint of water), and then washed by soaking face downwards in still water. Washing in running water will remove some of the colour. Washing is complete when the yellow tinge is discharged from the white of the picture.
REFERENCE
Uranium Toner, Photographic Facts and Formulas