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The workable formula from the great brochure "Testing methods for photographic gelatin (Pagi method)", 1964.
Iodide-stabilized silver chloride emulsion. With a cooking gelatin this formula gave me Grade 2-3 of contrast and about of 1/100 of bromide paper sensitivity.
3.6. Gaslight emulsion formula for photographic paper
3.6.1. Formulation
Solution A (55°C)
Distilled water……………………..400 ml
Gelatin………………………………30 g
20% citric acid..............................2 ml
Solution B (55°C)
Silver nitrate................................20 g
Distilled water............................100 ml
Solution C (about 45°C)
Sodium chloride……………………...9 g
20% citric acid.............................10 ml
Distilled water……………………..100 ml
Solution D (55°C)
Gelatin………………………………50 g
1% potassium iodide………………10 ml
Distilled water……………………..300 ml
3.6.2. Emulsification and ripening
Maintain solution A at 55°C and add solution B while stirring. After one minute at
55°C, add solution C at once while stirring and ripen for 40 minutes at 55°C. Then
add solution D and ripen for 10-20 minutes at 55°C.
3.6.3. Coating
Before coating, bring total volume of emulsion to 1.2 kg and coat in on barytaged
paper. The quantity of emulsion for coating shall be 4 ml per plate of cabinet size.
Iodide-stabilized silver chloride emulsion. With a cooking gelatin this formula gave me Grade 2-3 of contrast and about of 1/100 of bromide paper sensitivity.
3.6. Gaslight emulsion formula for photographic paper
3.6.1. Formulation
Solution A (55°C)
Distilled water……………………..400 ml
Gelatin………………………………30 g
20% citric acid..............................2 ml
Solution B (55°C)
Silver nitrate................................20 g
Distilled water............................100 ml
Solution C (about 45°C)
Sodium chloride……………………...9 g
20% citric acid.............................10 ml
Distilled water……………………..100 ml
Solution D (55°C)
Gelatin………………………………50 g
1% potassium iodide………………10 ml
Distilled water……………………..300 ml
3.6.2. Emulsification and ripening
Maintain solution A at 55°C and add solution B while stirring. After one minute at
55°C, add solution C at once while stirring and ripen for 40 minutes at 55°C. Then
add solution D and ripen for 10-20 minutes at 55°C.
3.6.3. Coating
Before coating, bring total volume of emulsion to 1.2 kg and coat in on barytaged
paper. The quantity of emulsion for coating shall be 4 ml per plate of cabinet size.