B&W Reversal with Hydrogen Peroxide

Fragomeni · Aug 15, 2021

YoIaMoNwater said:
Have you tried reducing the bleach time? That could also help to increase Dmax, although you’ll need to find an optimal time where the highlights are clear.

That could be worth experimenting with but it would be a fine balance. I’m really only seeing the Dmax issue with Fomapan, which is a thin emulsion anyway so that’s probably just what it is. Dmax with FP4 is better (although could be better) and Tri-X is much better from the little I’ve experimented with it — need to try it again though yo confirm because I messed up the process a bit last time I tried and my overall exposure was insufficient.

——

Has anyone tried this with Ilford 3200? I’ve seen reference to it reversing decently and I know DR5 can do it with good results. I’m in need of a faster film for reversal for better hand held times with my 35mm Grandagon because it requires a 2.5 stop center graduated ND and that loss of two stops is largely relegating me to a tripod when I want to use it at f22 where it really sings.

M-88 · Oct 23, 2024

I accidentally ended up having the necessary chemicals for this kind of reversal, so I thought I would give it a try, just out of curiosity. But I have a question:

Should the film be wet during the second exposure, or should I let it dry first? Re-spooling the wet film on the spiral, on the other hand, might be tricky.

SalveSlog · Oct 23, 2024

Wet, I'd say. And putting it back on the spool is easier if you do it under water.

Anon Ymous · Oct 23, 2024

M-88 said:
Should the film be wet during the second exposure, or should I let it dry first? Re-spooling the wet film on the spiral, on the other hand, might be tricky.

Just leave the film on the spiral, no need to take it out and respool, but have it immersed in water during re-exposure. I spin it under the lamp I use, just an ordinary household one. It used to be a 75W tungsten one, nowadays it's an led equivalent. About a minute or so from each side should be enough. Actually, it's probably massive overexposure.

M-88 · Oct 23, 2024

Anon Ymous said:
Just leave the film on the spiral, no need to take it out and respool, but have it immersed in water during re-exposure. I spin it under the lamp I use, just an ordinary household one. It used to be a 75W tungsten one, nowadays it's an led equivalent. About a minute or so from each side should be enough. Actually, it's probably massive overexposure.

I probably sound dumb, but I always thought "expose from both sides" meant removing the film from the spiral and exposing its entire length from both sides

Donald Qualls · Oct 24, 2024

I've done it on the spiral, and it works fine. All that's needed is to get enough light to all of the undeveloped halide to fully expose it. One trick I've read (but haven't tried) for plastic spirals is to fill a stainless salad bowl with water, drop the reel into it, and expose with a moving reflector lamp. One minute or so, then flip the spiral over and another minute on the other side.

M-88 · Oct 24, 2024

Donald Qualls said:
I've done it on the spiral, and it works fine. All that's needed is to get enough light to all of the undeveloped halide to fully expose it. One trick I've read (but haven't tried) for plastic spirals is to fill a stainless salad bowl with water, drop the reel into it, and expose with a moving reflector lamp. One minute or so, then flip the spiral over and another minute on the other side.

Thank you, I have a plastic spiral that has a transparent upper part - might be convenient for better exposure. I also have a roll of Rollei Infrared which turned out to be underwhelming in its near infrared role, so that's what I'm going to use.

relistan · Oct 24, 2024

I (carefully) unspool it from the stainless reel and hold it up to the light on both sides, then spool it back on. This is impossible with plastic reels, it won’t load wet. I’ve never scratched it doing this, but if you get good results without it, that’s safer.

YoIaMoNwater · Nov 15, 2024

M-88 said:
I probably sound dumb, but I always thought "expose from both sides" meant removing the film from the spiral and exposing its entire length from both sides

I use this bowl method where you don't have to remove the film from the reel and works perfectly.

M-88 · Nov 16, 2024

YoIaMoNwater said:
I use this bowl method where you don't have to remove the film from the reel and works perfectly.

Oooof! If that's you talking in the video, then props to you for using a Zenit! Mine resides somewhere in one of my drawers.

Back on the subject, though: peroxide bleach didn't work for me. It didn't bleach the negatives completely so I ended up with a mess. I should really try finding a higher concentrate, or just go with EDTA.

relistan · Nov 17, 2024

M-88 said:
Oooof! If that's you talking in the video, then props to you for using a Zenit! Mine resides somewhere in one of my drawers.

Back on the subject, though: peroxide bleach didn't work for me. It didn't bleach the negatives completely so I ended up with a mess. I should really try finding a higher concentrate, or just go with EDTA.

It takes a fair bit of testing with any kind of reversal process to get it right. The bleach might not be the problem. That said, the peroxide/EDTA/citric acid bleach is much better.

Donald Qualls · Nov 19, 2024

M-88 said:
or just go with EDTA.

EDTA won't work for B&W reversal. It converts the developed silver to a fixable form, but doesn't dissolve it away, and you'll get solid black film after light (or chemical) fogging and second development.

relistan · Nov 19, 2024

Donald Qualls said:
EDTA won't work for B&W reversal. It converts the developed silver to a fixable form, but doesn't dissolve it away, and you'll get solid black film after light (or chemical) fogging and second development.

Donald you can’t use it by itself. You use it with citric acid and peroxide, per the long thread I ran about it a few years ago and the posted formula here on the site and on my blog. There are of course other bleaches that have used it.

YoIaMoNwater · Aug 10, 2025

@relistan Did you manage to get a density reading for the Dmax and Dmin of Fomapan 400 in your process? I’m starting back reversal processing again and been testing some Fomapan 100 but the Dmax looks low from my protocol.

relistan · Aug 13, 2025

YoIaMoNwater said:
@relistan Did you manage to get a density reading for the Dmax and Dmin of Fomapan 400 in your process? I’m starting back reversal processing again and been testing some Fomapan 100 but the Dmax looks low from my protocol.

I believe so, will check notes and get back to you! It's not as dense as I'd like but it looks pretty good.

YoIaMoNwater · Aug 15, 2025

relistan said:
I believe so, will check notes and get back to you! It's not as dense as I'd like but it looks pretty good.

Thanks Karl! In the future I might send you more films to be analyzed if you have the time.

relistan · Aug 15, 2025

YoIaMoNwater said:
Thanks Karl! In the future I might send you more films to be analyzed if you have the time.

I am back from holiday and have my notebook. Looks like I didn't have my densitometer at the time and didn't record any densities in my notebook for the reversal. But yeah, send me some more films. I have a new address, though, so hit me up before you do!

Raghu Kuvempunagar · Nov 14, 2025

kentanghk said:
The patent relistan posted was very interesting and I did some preliminary test after reading.

Bleach C
Hydrogen peroxide (35%) 28.5g/L
Potassium hydrogen phthalate 7.15g/L
pH adjusted by NaOH to pH5

Bleach C worked surprisingly well.

Saw a related bleach formula being used colour reversal here:

600ml distilled water at 50C
81g potassium hydrogen phthalate (a mild crystalline acid)
ensure the phthalate has dissolved before adding the next ingredient
350ml 12% food grade peroxide
Adjust pH to 4.5 with 10% NaOH ( add a small amount at a time, be careful, it may fizz)
1g silver nitrate in 40ml water (important catalyst)
Water to make 1 Litre
Final should be around PH 4.4
Use at 38C

[Important: make sure to add the silver nitrate (or silver sulphate, citrate etc) before adding the NaOH to adjust the pH.]

Use of Silver Nitrate as the catalyst is interesting. No idea if this would work as is for B&W reversal but if anyone here is interested in testing, @adycousins might be able to share inisghts.

relistan · Nov 17, 2025

Raghu Kuvempunagar said:
Saw a related bleach formula being used colour reversal here:

600ml distilled water at 50C
81g potassium hydrogen phthalate (a mild crystalline acid)
ensure the phthalate has dissolved before adding the next ingredient
350ml 12% food grade peroxide
Adjust pH to 4.5 with 10% NaOH ( add a small amount at a time, be careful, it may fizz)
1g silver nitrate in 40ml water (important catalyst)
Water to make 1 Litre
Final should be around PH 4.4
Use at 38C

[Important: make sure to add the silver nitrate (or silver sulphate, citrate etc) before adding the NaOH to adjust the pH.]

Use of Silver Nitrate as the catalyst is interesting. No idea if this would work as is for B&W reversal but if anyone here is interested in testing, @adycousins might be able to share inisghts.

Thanks. This looks familiar, it may be from a patent. When we worked on our formula, I found several patents using silver nitrate in the bleach (for B&W as well).

Raghu Kuvempunagar · Nov 17, 2025

relistan said:
Thanks. This looks familiar, it may be from a patent. When we worked on our formula, I found several patents using silver nitrate in the bleach (for B&W as well).

It is adapted from this Eastman Kodak patent. See Bleach F.

It is an expensive bleach but if one wants to avoid dichromate and permanganate, the price could be worth paying if the bleach works smoothly.

B&W Reversal with Hydrogen Peroxide

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