View Full Version : Experiment - Developer + selenium

4-Jul-2018, 16:39
In case you were wondering what happens when you add Selenium to LPD Paper developer....

I had some LPD with some age on it and decided to use it up but on a whim added 25-30mls of selenium to the the 500mls of LPD 1:2 working strength then topped up to make a liter. I ran the print through normal LPD 1:2 for 2 minutes for most of the development, then I dunked the print into the Selenium mixture , then stop bath, fix, rinse, hypo clear, and wash as usual. I gave these extra wash time.

At 30 seconds in the selenium mixture the paper shifted to a creamy fogged color where it was previously white while dark silver tones took on a cold bluish cast. Darktones deepened dramatically.
Repeated with second image at 10 seconds and the fogging still occurred but was not as extreme. Blacks still turned toward blue.
Even 5 seconds gave a fogged look to the highlights but the blue-black is not as extreme.
Paper was Ilford MGFB Classic Glossy

The developer-selenium mixture was a dark gray after 5 or six prints through the solution and the stop and fix became contaminated but still worked for my few remaining prints.

If anyone wants to repeat my experiment I would recommend starting with even less selenium maybe only 10mls per liter. I would be interesting to hear of results with different developers and papers.
It might even make for an interesting second pass developer after bleaching and may not be as extreme due to less silver in the processed paper.

5-Jul-2018, 08:14
I assume you used selenium toner, not elemental selenium. In which case, note that there is thiosulfate (fixer) present in most (all?) commercial selenium toners, which complicates matters, which is also true for ammonia. The thiosulfate will obviously partially fix the latent image while the ammonia could very well play a role in the formation of fog. But of course, since silver is more noble than selenium, bringing a silver halide in contact with selenium will result in the silver stealing an electron and becoming metallic at the expense of the selenium. So fog is a natural consequence.

If you want to promote warmer colors during development, try adding a little (!) ammonium chloride to the developer.

Doremus Scudder
5-Jul-2018, 11:05
I don't know really that this would cause a lot of fog, rather selenium toning of the unexposed silver halides that had not yet been fixed out. This would explain the "creamy whites" the OP experienced. Or maybe it's a two-step process: the silver halides react with the selenium forming the fog and then this gets toned by the selenium as well. I imagine that this technique might be useful (if it could be tamed enough) for those who don't like the bright white base of most papers these days.


5-Jul-2018, 11:07
Koraks, thanks for the tip about the Ammonium Chloride. I used Kodak Rapid Selenium Toner so yes it has some fixer built in which is why I only used a small amount. Nice to know the science behind it.

I know Alum (sulphate of Aluminum and Potassium) is used in the tanning industry for dyeing sepia/brown tones. I wonder if it would mix well with a developer since it already contains Potassium Bromide.