Caution: Uranium nitrate is highly toxic--do not allow it to come in contact with skin-- wear thick gloves, goggles, a dust mask and a long-sleeved shirt.
Use tongs.
Uranium Toner
No. 1
No. 2
Uranyl nitrate 10% sol
25 ml
25 ml
Potassium oxalate 10% sol
25 ml
--
Potassium citrate10% sol
--
25 ml
Pot. Ferricyanide 10% sol
10 ml
10 ml
Ammonium alum 10% sol
50 ml
--
Hydrochloric acid 10% sol
5 ml
50 ml
Water to make
1 liter
1 liter
A normal print may be lightly toned by a brief immersion, but complete toning requires a print of low contrast. Formula number 1 produces redder tones than number 2. Tone for 2
to 10 minutes. Sodium citrate may be substituted for potassium citrate. The citrate solution may be preserved with a small amount of antiseptic such as phenol. In order to prevent
staining, the print must be washed thoroughly to remove all hypo. To remove the yellow stain after toning, the following bath should be used several times in succession, as necessary
Potassium citrate
5 grams
Sodium sulphate (not sulphite)
25 grams
Water
1 liter
To ensure permanence, use the following sulphiding bath:
Sodium sulphide
10 grams
Hydrochloric acid
1 ml
Water
1 liter
Or, if the sulphide bath is not used, to remove residual silver from a fully toned print use the following acid fixer. Follow with a thorough wash in acidified water.
Hypo
50 grams
Sodium acetate
10 grams
Acetic acid 10% solution
10 ml
Water to make
1 liter
Uranium Toner
Distilled Water
500 cc
Glacial Acetic Acid
12.5 cc
Potassium Ferricyanide
0.7 g
Uranium Nitrate
0.7 g
Distilled Water to Make
600 cc
Uranium toning is a modified form of intensification not suitable for dense prints. Less water may be used to speed the toning action.
Uranium Toner
Sensitizer
Uranium Nitrate
10.5 g
Distilled Water
1 liter
Developer
Potassium Ferricyanide
10.5 g
Glacial Acetic Acid
25 ml
Distilled Water
1 liter
Mix equal parts A and B. Dilute further if toning action proceeds too rapidly. Print color varies depending upon the developer used when making the print. Toning begins
immediately. Just before the desired density is reached, the print should be transferred to a bath of weak acetic acid (4 ml in 300 ml water) for 2 to 3 minutes. This is followed by a soak in
still water until the yellow stain disappears. Running water will cause blotches. A 2% solution of citric acid or a 1% solution of oxalic acid are said to give clearer tones than the acetic
acid.
