Bromine Gas Bleaching Test #1

Thought I would post an update and share what happened a few weeks back.

Disclaimer: Needless to say Bromine, especially gas/vapour/fumes etc (and other halogens) is very dangerous. Don't do what I do.


So I pulled film out of the bromine gassing area into light, and then gassed it again to bleach away light induced fog, 'cept I left it in there for over a week to let the bromine escape and dissipate completely..

Anyway, the reels I used in the tank (apart from bottom one, which was touching acidic+oxidising solution) have bromine deposits, as did the film.. which was kinda half melted somehow. Awesome!

I'll try bromine chlorine first.. as it's a gas at the working temps I use, rather than bromine which has a boiling point of 58.8 C (above my working temps, hence it will deposit back onto surfaces at room temp). Though I'd love to try Iodine bleaching as a method of not only removing fog, but restoring ancient film to full speed, and even increasing speed depending on iodide content already in the film.

My Theory On Gas Bleaching:

My theory with gas bleaching is that I can rehalogenate silver to silver halide with a gas bleach.

You can do this in solution with a bleach, but this will wash out sensitising dyes, anti-halation layer, and other things, which reduces film speed and film spectral sensitivity.

With gas bleaching, that stuff stays where it is, hence you can potentially recover full film speed, or even potentially increase film speed of both b&w and colour film that has been fogged due to age, or film that has been pulled out in the light.

You could go so far as to leave film out in the sun to reduce to finer silver grains, and gas bleach back to silver halide, for a much finer grained (and very high resolution!) slow speed high contrast film - this can be applied to colour films too!

It doesn't take much halogen gas at all, so it can be performed in a film tank easily to sit in a small amount of gas, bleaching goes by very fast from what I can see.

More testing is needed.

Film Re-cycling Experiments Part 1.

After ripping out 70 odd ft of Vision1 500T (15 years old) out of a bulk loader and sitting it on my floor in the light (to make room for new Vision2 50D and Vision3 500T for bulk loading... still got another 700 ft of Vision1 500T in cans), I thought of something to do with it.

Cut some of it up, loaded it in a tank, processed it in some Xtol, now then I chilled a weak solution of potassium ferricyanide and potassium bromide to bleach the film back to all silver halide (just silver bromide) slowly to make a high contrast, fine grain, slow speed b&w film.. though I can try putting it through C-41 to get the CMY dyes (wont be a real colour image, but can treat it as a b&w during scanning for chromogenic b&w for IR dust removal), or just regular b&w processing.

The stuff still in the can and old expired film sitting around I have that's now shitty quality (Kodak Gold 100 from 2000), I can try just bleaching the fog (specks of elemental silver) away back to silver halide to restore the speed and denisty range.

If I want to keep it as useful colour film, that will have to be gas bleaching, so that it doesn't wash out the anti-halation layer and the spectral sensitisation dyes etc.

I also figured I could bake some film out in the sun until it is all reduced to metallic silver, and gas-bleach it back to silver halide for a high contrast, fine grain, slow colour film.

Things to try

Been in Melb for 6 weeks now...


Got a few things to try... pull-processing C-41 film, which I've already done in Rodinal and re-developed to colour before.. though that was 14 stop pull... good for daytime long exposure with no filters.

Got some old ISO 400 film that seems a bit crap and foggy at 400... though I did accidentally overdevelop it. Anyway, expose it at EI 50 and develop for 2 min 45 sec is the plan to see how it comes out.

Some bigger pulls with shorter times or C-41 with a 1+1 or 1+2 dilution and EI 12 and slower just to have a play.

Need to find some HCl from a pool shop to finish my concentrated 2 part colour negative developer.


Also got a roll of Rollei Pan 25 to test out.. not sure what to actually use it on though is the problem.



I want to try some Ektar 100 in 35mm lab-developed, and developed 'normally' (EI 100) in my concentrated developer (1+1+50), and pulled to EI 25 (1+1+100), with 8000 dpi Flextight 848 scans - just to ascertain differences.


The unbranded 400 ISO C-41 film shot @ EI 400, developed 3 min 45 sec accidentally and not agitated much (2 stop accidental push, was very dense and crappy), developed in Kodak Flexicolor at home, colour corrected (since it's C-41, posting orange negatives would be kinda odd).