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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
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No. 1
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No. 2
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Uranyl nitrate 10% sol
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25 ml
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25 ml
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Potassium oxalate 10% sol
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25 ml
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--
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Potassium citrate10% sol
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--
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25 ml
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Pot. Ferricyanide 10% sol
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10 ml
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10 ml
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Ammonium alum 10% sol
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50 ml
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--
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Hydrochloric acid 10% sol
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5 ml
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50 ml
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Water to make
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1 liter
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1 liter
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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
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Potassium citrate
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5 grams
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Sodium sulphate (not sulphite)
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25 grams
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Water
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1 liter
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To ensure permanence, use the following sulphiding bath:
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Sodium sulphide
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10 grams
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Hydrochloric acid
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1 ml
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Water
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1 liter
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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.
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Hypo
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50 grams
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Sodium acetate
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10 grams
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Acetic acid 10% solution
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10 ml
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Water to make
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1 liter
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Uranium Toner
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Distilled Water
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500 cc
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Glacial Acetic Acid
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12.5 cc
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Potassium Ferricyanide
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0.7 g
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Uranium Nitrate
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0.7 g
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Distilled Water to Make
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600 cc
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Uranium toning is a modified form of intensification not suitable for dense prints. Less water may be used to speed the toning action.
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Uranium Toner
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Sensitizer
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Uranium Nitrate
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10.5 g
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Distilled Water
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1 liter
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Developer
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Potassium Ferricyanide
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10.5 g
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Glacial Acetic Acid
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25 ml
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Distilled Water
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1 liter
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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.
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Cyanotype/Uranotype
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Sensitizer
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Green ferric ammonium citrate
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7.1 grams
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Uranic nitrate
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2.3 grams
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Water
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30 ml
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Developer
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Potassium ferricyanide
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1.4 grams
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Water
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30 ml
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