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Photography Online 1st shoot with glass plate
- Thread starter Peter B
- Start date
- Joined
- Dec 19, 2017
- Messages
- 3,548
It's almost exactly 40 years to the month since I last made and coated photographic emulsions for commercial use, normally you add adjuncts like hardeners prior to coating. For basic hardening typically Chrome Alum, and Formalin, are added, the actual level is extremely low, but very effective.
There are ways of coping with poorly hardened plates, or films. First add a hardener to the developer, second use a hardening stop bath, third use a hardening fixer. Or use a Pyro tanning developer as they harden the emulsion during development, and Pyrogallol was the developing agent used with very early Silver Gelatin plates.
ISO 2 is a bit slow, I'd guess the emulsion I made was ISO 6, I did make faster while researching, but base fog rises slightly , and that's fine for film use, but the emulsion I made was for projection printing. Speed & Contrast was almost identical to Ilfospeed Gd 3 emulsion, which I trialed as Ilford wanted to supply it to me
That fell through when I mentioned at a business lunch that Barfen sold a Liquid emulsion, when Ilford approached Barfen to suggest buy from them they had a shock. Barfen's emulsion came out of the back door of Ilford's London Nuclear emulsion lab.
Changing the subject back to the Video. I like some movent in grasses, trees, ferns, a different way of working.
Ian
There are ways of coping with poorly hardened plates, or films. First add a hardener to the developer, second use a hardening stop bath, third use a hardening fixer. Or use a Pyro tanning developer as they harden the emulsion during development, and Pyrogallol was the developing agent used with very early Silver Gelatin plates.
ISO 2 is a bit slow, I'd guess the emulsion I made was ISO 6, I did make faster while researching, but base fog rises slightly , and that's fine for film use, but the emulsion I made was for projection printing. Speed & Contrast was almost identical to Ilfospeed Gd 3 emulsion, which I trialed as Ilford wanted to supply it to me
That fell through when I mentioned at a business lunch that Barfen sold a Liquid emulsion, when Ilford approached Barfen to suggest buy from them they had a shock. Barfen's emulsion came out of the back door of Ilford's London Nuclear emulsion lab.Changing the subject back to the Video. I like some movent in grasses, trees, ferns, a different way of working.
Ian
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