Ferrous Sulphate developer for paper

phnompenhphotography · Apr 27, 2021

Hi all

I have looked but found nothing definitive, is it possible/worthwhile to use a basic ferrous sulphate developer to develop papers exposed in a camera. Either to make paper negs or for reversal processing?

Thanks
Andy

Donald Qualls · Apr 27, 2021

I don't know any reason it wouldn't work, but there are good reasons organic developers replaced inorganic (like ferrous sulfate) more than 120 years ago. Were inorganic developers ever used for gelatin emulsions, or were they confined to collodion?

phnompenhphotography · Apr 27, 2021

Thanks, I can't see why they wouldn't work either but I can only find references to collodion. I will just have to try it and see when my papers and such arrive I guess. I don't know if they were ever used for gelatin.

Donald Qualls · Apr 27, 2021

Might be simplest to first do a drop test on a film leader.

In the light, put a drop of the working solution developer on a film leader clip, and time how long it takes the film to turn black where the drop is. Development time would be five times this long as a starting point toward establishing normal contrast.

General Treegan · May 5, 2021

Hi!
Ferric developers work quite well on modern films. I'm researching it and doing some tests. Here is one, Plus x 16mmin ferric citrate developer for 24min at room temp [around 19-20ºC]

Donald Qualls · May 6, 2021

Nice! What film speed did you get?

Ferrous sulfate is easy to get in garden stores (some plants need more iron than is naturally in the soil). I think I recall that the other reason ferrous sulfate developers were used on collodion is that the developer needs to be acidic to penetrate the sensitized layer. Obviously not the case with gelatin.

Ferrous Sulphate developer for paper

phnompenhphotography

Donald Qualls

phnompenhphotography

Donald Qualls

General Treegan

Donald Qualls

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