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cyrus
25-Jan-2008, 15:01
We are experimenting with glass plates and need formulas for emulsions.
Nothing fancy, will be using store-bought gelatin. I have the Silver Gelatin book too already but it mainly talks about using pre-manufactured emulsion like Silver Light, which is mainly for paper and doesn't have the range for negatives . Do you have any formulas for negalives?
SAShruby
25-Jan-2008, 15:27
There is a photo engineer on APUG forum. It is a great source for what you're looking for.
Oren Grad
25-Jan-2008, 16:29
Check out the Silver Gelatin Based Emulsion Making & Coating forum at APUG. Ron Mowrey, retired from Kodak, leads discussions there that are full of fun facts and good advice for emulsion-tinkerers.
athanasius80
26-Jan-2008, 13:15
Beware of 1880s dry plate recipes. I've talked to a couple emulsion chemists, and they both said that pre-1930s recipes are quite difficult to use. Apparently early emulsions used active gelatin with a higher sulfur content, and that isn't easily procurable these days. But with everything photographic YMMV. Good luck!
cyrus
26-Jan-2008, 20:51
Beware of 1880s dry plate recipes. I've talked to a couple emulsion chemists, and they both said that pre-1930s recipes are quite difficult to use. Apparently early emulsions used active gelatin with a higher sulfur content, and that isn't easily procurable these days. But with everything photographic YMMV. Good luck!

Yes that's one of the issues I am dealing with. The sulphur acted as a sensitizer whch increased speed.
athanasius80
26-Jan-2008, 22:32
I've corresponded with the engineer mentioned above about the sulfur issue. He said its more trouble than its worth to increase the sulfur content to mimic the gelatin of a century ago. Kinda a bummer, but the recipes might still work.
Kirk Keyes
27-Jan-2008, 22:22
Google free books on-line.

Here's a pdf of a classic emulsion book I have on my website. It's not the cleanest formatting, but it is readable.

http://www.keyesphoto.com/KDKtech-E._J._Wall-Photographic_Emulsions.html

As far as sulfur sensitization, Ron Mowrey has used 100 mg sodium thiosulfate pentahydrate per mole of silver in the emulsion.