Reversal processing using hydrogen peroxide bleach

snowcave · Nov 22, 2019

I'm interested in getting into reversal processing film, most instructions (and commercial kits) use a potassium permanganate or dichromate bleach. Just as I was getting ready to order the necessary chemicals, I came across this video which indicates a combination of household hydrogen peroxide and vinegar can be used instead. Obviously with the permanganate bleach being finicky and the dichromate bleach being particularly toxic this is very appealing.

That being said, surely this would already be the standard for home development if it didn't have any downsides. Has anyone been able to compare the results of a peroxide bleach to the traditional methods?

removed account4 · Nov 22, 2019

hi snowcave
have you seen this thread ?
https://www.photrio.com/forum/threads/reversal-print-processing-video-new-approach.153447/
it doesnt' use vinegar but citric acid to activate household peroxide and as you can see in the thread, it works really well
i dabbled with this process cause i am not a fan of crazy chemicals, and this seemed just low tech enough..
good luck !
john

dabsond · Nov 22, 2019

I saw this as well and am interested in trying it. I will probably hand roll a 12 exp roll and give it a shot.

Raghu Kuvempunagar · Nov 22, 2019

Assuming that the bleaching step indeed goes to completion, ie removes the silver image completely from the film, there's not much of a case for comparison, isn't it? The result you get depends primarily on the first developer. If you still want you can keep all steps but the bleach the same and compare the results.

Pentode · Nov 22, 2019

I was doing some reading up on peroxide/citric acid bleach about a year ago (for the same reasons) and, from most of what I found online, peroxide bleaches are much slower but just as effective. I never got around to trying it personally.

snowcave · Nov 22, 2019

Thanks all!

Raghu Kuvempunagar · Nov 26, 2019

snowcave said:
I came across this video which indicates a combination of household hydrogen peroxide and vinegar can be used instead.

In the video, the presenter claims that the developing time with the first developer is the same for all films. This hasn't been my experience with different B&W films I've used in reversal processing. Maybe HC-110 that the presenter uses is magical in this respect, I don't know.

Wearing gloves, lab apron and goggles is advisable when dealing with bleach.

guangong · Nov 26, 2019

There may be an advantage to hydrogen pyroxide-citric acid for reversal processing a roll of still film, but from comments made by contributors to thread, most likely not vigorous enough for reversal processing of movie film. So I’ll stick with dichromate formula for all my reversal processing.
We were taught how to handle hazardous chemicals in chemistry class in high school. Old school lab work.

removed account4 · Nov 26, 2019

the benefits to me aren’t the handling of dichromate or sulfuric acid it’s more like I don’t want to deal with yet another nasty chemical in my darkroom... for paper and film citric acid ( used as veggie wash ) and grocery store. Dollar store pharmacy strength peroxide ( used in toothpaste and as an antiseptic ) aren’t nasty chemicals ... and they seem to work well... never used it with film ( movie or stilly ) but seems others have with success ( at least stilly ). ... have fun !

abruzzi · Nov 26, 2019

In the video he pulls the film off the spool to re-expose it. At least with my spools, there is no way that film would go back on unless I waited a day for everything to dry off. Is it sufficient with plastic AP spools or Patterson spools to leave the film on the spool and just shine the light in from the sides?

snowcave · Nov 26, 2019

I've heard of people doing that, can't say for sure though. The Darkroom Cookbook recommends using steel reels only for ease of un/re-rolling, which actually contradicts advice I've seen elsewhere to use plastic reels as the (traditional, no idea about peroxide) bleach might damage the steel or the solder or something. I only have Hewes reels so I think I'm going to chance it.

(I decided to just go with the tried and true dichromate bleach and be extra careful)

Raghu Kuvempunagar · Nov 26, 2019

abruzzi said:
In the video he pulls the film off the spool to re-expose it. At least with my spools, there is no way that film would go back on unless I waited a day for everything to dry off. Is it sufficient with plastic AP spools or Patterson spools to leave the film on the spool and just shine the light in from the sides?

You can get rid of re-exposure and developing by using chemical fogging (dithionite).

See https://www.flickr.com/groups/1924424@N22/discuss/72157629499928508/ for a detailed description of reversal processing.

destroya · Nov 27, 2019

yeh, use a chemical re-exposure. much easier. the link above to peter's process is the one i use and have for many years with great repeatable results.

Rudeofus · Nov 27, 2019

abruzzi said:
In the video he pulls the film off the spool to re-expose it. At least with my spools, there is no way that film would go back on unless I waited a day for everything to dry off. Is it sufficient with plastic AP spools or Patterson spools to leave the film on the spool and just shine the light in from the sides?

Yes, shining bright light from both sides also works.

If you do unspool the film from plastic spindles, you can easily get it back onto the spindle under running warm water. Damp gelatin sticks like hell, but as soon as the film is really wet, it will slip right on.

MattKing · Nov 27, 2019

Rudeofus said:
If you do unspool the film from plastic spindles, you can easily get it back onto the spindle under running warm water. Damp gelatin sticks like hell, but as soon as the film is really wet, it will slip right on

Particularly if you can see what you are doing!

guangong · Nov 28, 2019

Re-exposure to light is the tried and true method. I have not really had satisfying success with chemical re-exposure. No fussiness required when using light.

Raghu Kuvempunagar · Nov 28, 2019

guangong said:
Re-exposure to light is the tried and true method.

Chemical fogging has been used to develop direct positive movie film. Kodak's direct positive film developing outfit for direct positive panchromatic film 5246 had Dithionite-based fogging redeveloper FD-70:
https://125px.com/docs/techpubs/kodak/j6.pdf

Raghu Kuvempunagar · Nov 29, 2019

Alessandro Serrao said:
The chelicals indicated are hard to find and are short-lived. Plus some of them are toxic anyway.
Dimethylamine borane, hydrazine sulfate, dithionite, hcl-cysteine, etc...

Kodak's fogging redeveloper doesn't use dimethylamine borane or hydrazine sulfate. Only dithionite and cysteine hydrochloride. Dithionite is relatively less toxic and is quite ubiquitously available as Iron Out and its competitor products for rust and stain removal. As only 5g dithionite is needed per liter of fogging developer working solution, it can be prepared fresh every time. Cysteine hydrochloride is there in the formula only to clear highlights and can be skipped if not available.

If you are using dichromate for bleaching then you are already handling a more toxic chemical in reversal processing. Nevertheless, adequate precautions need to be taken.

guangong · Nov 29, 2019

As a home processor of reversal processing for movies, I have gotten more consistent result using light rather than chemical re-exposure. Processing labs, using automatic equipment that allows consistency of chemicals, temperature, time and other variable would find chemical reversal more efficient and practical. There is no way I am able to meet the extremely short development times proscribed by Kodak for Tri X movie film. For processing a couple rolls of 35mm it 120 film, using chemicals for re-exposure is hardly worth the bother.
Does Kodak still make the reversal kit.? I haven’t used it for many, many decades. Find it more convenient to mix chemicals as needed.

Raghu Kuvempunagar · Nov 29, 2019

guangong said:
Processing labs, using automatic equipment that allows consistency of chemicals, temperature, time and other variable would find chemical reversal more efficient and practical.

For still film reversal, I can't see why consistency of chemicals, temperature and time can't be achieved for fogging redeveloper. Further, redevelopment is till completion and is therefore more robust to variation in temperature and time.

guangong · Nov 29, 2019

Raghu Kuvempunagar said:
For still film reversal, I can't see why consistency of chemicals, temperature and time can't be achieved for fogging redeveloper. Further, redevelopment is till completion and is therefore more robust to variation in temperature and time.

Not that it cannot be consistent, but what I was trying to imply was, as noted earlier, a slide is viewed one at a time so that slight variations are not notable, whereas with motion pictures an ever so slight variation in final development becomes instantly noticeable upon projection. With chemical re-exposure, just another solution to worry about. And light is easily available and cheap.
On the other hand, whatever works for a given individual is ok.

Raghu Kuvempunagar · Nov 29, 2019

I find it convenient that dithionite can be mixed fresh everytime not needing to be stored and replenished. Once mixed, it keeps well only for a short duration of time. It's possible that inconsistencies observed by some are due to not using the dithionite based fogging redeveloper immediately after mixing. Also, if one is using dithionite and not Iron Out, the solution needs to be alkaline, a fact easy to forget but can cause inconsistencies.

Raghu Kuvempunagar · Dec 3, 2019

Alessandro Serrao said:
I've got uneven fogging results by using plain dithionite in an alkaline solution.

Can you give more details of the problem you faced? Also pics of the slides showing uneven fogging would be helpful in understanding the problem.

Reversal processing using hydrogen peroxide bleach

Moderator

Privacy & Transparency

Privacy & Transparency