Edwal Thermo Salts

Hello Everybody,

My search to find a home brewed substitute for FG7 continues. In the meantime, in rereading Dr. Lowe's little book, I have once again wondered what the Edwal Thermo Salts were...actually, I know what they were, a compound to help in controlling high temperature development. But does anyone out there have an inkling as to what the actual chemical composition of the stuff was? As always, I'd appreciate the benefit of your knowledge.

Cheers,
John

It was sodium sulfate and was used to prevent emulsion swelling at higher than normal temperatures. It's use should not be necessary with modern pre-hardened films unless development is above 80F.

Thank you.

Thank you, Gerald. I'd rather thought you might have the answer. Much appreciated.

Cheers,
John