B&W Reversal with Hydrogen Peroxide

[Boldizsar]

I got lousy grades in Chemistry and Physics, so I beg your forgiveness for my cluelessness in advance..... having gotten that out of the way, can anyone tell me in plain English how much glacial acetic acid and how much distilled water I would need to mix with 12% Hydrogen Peroxide to get a liter of bleach?

and while I'm here, is there a consensus out there in terms of developer to use in conjunction with Hydrogen Peroxide based bleach? I saw one video promoting HC-110 and another using caffenol in connection with bleach made with citric instead of acetic acid. Has anyone ever considered others?

 

[relistan]

I got lousy grades in Chemistry and Physics, so I beg your forgiveness for my cluelessness in advance..... having gotten that out of the way, can anyone tell me in plain English how much glacial acetic acid and how much distilled water I would need to mix with 12% Hydrogen Peroxide to get a liter of bleach?

and while I'm here, is there a consensus out there in terms of developer to use in conjunction with Hydrogen Peroxide based bleach? I saw one video promoting HC-110 and another using caffenol in connection with bleach made with citric instead of acetic acid. Has anyone ever considered others?

Hi, welcome to Photrio. This thread is about some experiments. I suggest starting at the beginning of this thread.

 

[relistan]

Interesting! If silver could accelerate the bleach, then the question that arises is why couldn't the silver in the negative image itself act as the accelerator in case of Fomapan 400. Maybe the antihalation layer of Foma 100R has some other stuff besides the silver.

I had posited earlier that seasoned bleach might be stronger than fresh... still just a theory. But it’s possible there is something else in the R100. It would have to be something that can survive 12 minutes in Ilford Multigrade 1+5, though. Another metal?

 

[relistan]

Latest results from today (not exciting scenery: test shots). These are the Fomapan 400 bleaching at 22C. I think I could have left them in a little longer (you can see dark mottling in the sprocket holes), but it works.

First developer needs some attention. I will try thiosulphate again.

 

[relistan]

Updates from more testing today and some changes. I finally got ahold of a copy of Haist's book Volume 2, which helped a lot. The results are drying and I will scan later. But I learned some more things.

4 interesting outcomes:

1. The "seasoned" bleach can now run a roll in 2 mins at 20C. Sitting overnight, contrary to my hypothesis, actually seems to have strengthened it further. I hope it doesn't keep getting faster. There's a point where it's too fast! 2 minutes is about the same as dichromate bleach times as I read.
   
2. I got the first gold staining that I have yet seen with the peroxide/vinegar bleach. It's pretty subtle, but definitely there (see hypotheses below)
3. I added 4 g/L sodium thiosulfate after realizing the main problem I must have had before was not the film and thiosulfate was that the multigrade developer 1+12 was not active enough to overcome it. 1+5 appears to be.
   
4. Extensive testing with blackening down and bleaching and redeveloping small sections of film led me to adjust development times, shortening 1st dev and lengthening second dev.

The sodium thiosulfate does seem to have brightened up the highlights a bit. I think there might be room for more now that the 1st developer is stronger.

Theories about the gold/brown staining:

• @Raghu Kuvempunagar quoted the passage from Haist describing where staining can occur if bleaching outpaces the ability of the emulsion to pass through the ions
• It may also be that the "seasoned" bleach is now fully saturated with silver acetate and cannot absorb any more

I am not enough of a chemist to understand if one of the common clearing mixes would work with silver acetate so I might just have to try. They are either sodium sulfite, or sodium metabisulfite normally from the specs I have seen. Haist describes a balanced mix of both as an option. Anyone know this and have thoughts on it?

V3 Process:
Bleach times and temperature reflect seasoned bleach. Lacking that, you will need to run bleach at 40C for 6-10 mins, by inspection.

Chemicals:

• First developer: Ilford Multigrade Developer 1+5, Sodium Thiosulfate 4g/L
• Second developer: Ilford Multigrade Developer 1+9
• Bleach: Hydrogen Peroxide 3% 300ml + 21ml distilled malt vinegar (white vinegar equivalent), seasoned with some film, including Fomapan 100R.
• Fixer: Ilford Rapid Fixer (any rapid fixer will do). Hardener might be a good idea. I have not tried.

Process (to be run at 20C):

1. Develop 1. Run the first developer for 8 minutes at 20C. Agitate as you normally would. I invert twice every minute.
   
   
2. Wash. Use at least three changes of water. Ilford Multigrade Developer really sticks to film so you may see the first two baths turn yellow. You don’t want to carry that over into the bleach!
   
   
3. Bleach for about 2 minutes. It goes fast. Do this in subdued light, by inspection. When you see bubbles, agitate the film to slow the reaction down. You should see the whole film turn nearly the same color, and a faint positive image. Different films turn different shades of gray. Once nothing else is changing for awhile, you are done. For me this is about 6-10 minutes.
   
   
4. Wash in the same manner as above.
   
   
5. Re-Exposure Take the film from the spool and hold it between your hands, one on each end. Use a tungsten or halogen light and really, really expose it. It’s amazing how much light the film really needs to get fully, absolutely exposed. 1 minute or so is probably enough. Keep the film back about 25-30cm from the light source. You should avoid sunlight or other UV light sources to keep the film from printing out. Additionally, fluorescent lights will likely not give you full exposure.
   
   
6. Develop 2. Run the second developer for 8 minutes.
   
   
7. Wash in the same manner as above
8. Fix per your normal black and white process
9. Wash per your normal black and white process

 

[Raghu Kuvempunagar]

@relistan: Interesting experimental observation again!

Here's a radically different hypothesis. What you observed has nothing to do with seasoning or Fomapan 100-R. Rather peracetic acid synthesis from peroxide and acetic acid is not instantaneous and takes several hours to days based on the strength of the peroxide used. At the strength of peroxide used in your experiments, peracetic acid concentration reaches its maximum after a few days.

This hypothesis is based on a research report that gives data for 30% peroxide (peak concentration observed after 80-90 hours) and 90% peroxide (peak concentration observed after thirty minutes).

So, you may want to mix acetic acid and peroxide and store it well for a couple of days (or more) before using the mix as the bleach in reversal. Use a mole ratio of 1.5:1 peroxide to acetic acid as in the research report. Maybe it will do the bleaching in just 2 minutes in room temperature. If it does, it'll be your new year gift to photrio community. If it doesn't, you can curse me.

 

[relistan]

@relistan: Interesting experimental observation again!

Here's a radically different hypothesis. What you observed has nothing to do with seasoning or Fomapan 100-R. Rather peracetic acid synthesis from peroxide and acetic acid is not instantaneous and takes several hours to days based on the strength of the peroxide used. At the strength of peroxide used in your experiments, peracetic acid concentration reaches its maximum after a few days.

This hypothesis is based on a research report that gives data for 30% peroxide (peak concentration observed after 80-90 hours) and 90% peroxide (peak concentration observed after thirty minutes).

Thanks for the link! Will digest that tonight.

I think this makes sense. And I think this may be why the bleach I made yesterday is stronger today. But I think it takes a catalyst to kick it off properly. I'll see what the report says about it when I read through it.

I think the silver in the 100R is the catalyst. I started yesterday with day old bleach. I had thought it might have gotten stronger overnight so I tried it on a little strip of film at room temperature. Nothing happened. It was not noticeably stronger. I then decided to try the Fomapan 100R and you know what happened.

But, after the first incident with Fomapan 100R yesterday, I mixed up new bleach from scratch. Worried that something weird was going on I tried to bleach some Fomapan 400 to prove the newly mixed bleach was normal. It behaved normally. I then ran the second section of Fomapan 100R with images on it. It immediately reacted strongly and behaved the same as the day old bleach I had tried to use the first time. This new batch, mixed 30 minutes or so beforehand, was the one that I ran at 22C yesterday with Fomapan 400. The reaction from the Fomapan 100R somehow made it stronger in minutes. It's quite a reaction with that film. I read that silver is a catalyst for this peroxide/acetic acid reaction and I still think that's what happened in that case.

But in the case of it being stronger today, I think you are right about why.

So, you may want to mix acetic acid and peroxide and store it well for a couple of days (or more) before using the mix as the bleach in reversal. Use a mole ratio of 1.5:1 peroxide to acetic acid as in the research report. Maybe it will do the bleaching in just 2 minutes in room temperature. If it does, it'll be your new year gift to photrio community. If it doesn't, you can curse me.

I think this makes sense and is worth a shot. But I don't want bleach any more powerful than this! In order to achieve something more reasonable, I think I might need to dilute it further in that case.

I'll post back when I've read that report. Thanks!

 

[studiocarter]

Hot hydrogen peroxide and vinegar was tried with 8mm movie film. Reticulation happened. Pictures looked like alligator skin with tattoos. Best to change temperatures very gradually.

 

[falotico]

Hot hydrogen peroxide and vinegar was tried with 8mm movie film. Reticulation happened. Pictures looked like alligator skin with tattoos. Best to change temperatures very gradually.

Silver metal is a catalyst for decomposing H2O2 into H2O and O2 (gas). Since O2 (gas) is LESS soluble in aqueous solutions at a higher temperature, raising the temperature of the solution should cause more O2 to bubble out of solution. This probably causes the reticulation that was seen.

 

[kentanghk]

Very interesting! Is the silver nitrate acting as an intensifier?

I was following an old Kodak patent (EP0678783A1) and apparently adding some silver salt to the bleach could speed up the bleaching.
Here is the bleach formula I tried:

Water 750mL
Citric acid monohydrate 45g
30% hydrogen peroxide 100mL
Adjust pH to pH 4.5 by 50% sodium hydroxide solution
Silver nitrate 0.80g
Water to make 1000mL

Aim pH 4.4

 

[Raghu Kuvempunagar]

I think it takes a catalyst to kick it off properly. I'll see what the report says about it when I read through it.

The research report I shared earlier says that 1% sulphuric acid is the catalyst used in their experiments on peracetic acid synthesis from peroxide and acetic acid. If one wants to get 1% sulphuric acid without having to deal directly with sulphuric acid, ~40g/l of sodium/potassium hydrogen sulphate can be used.

It is unlikely that Fompan 100R emulsion is the source of low amounts of sulphuric acid in your experiments.

 

[relistan]

I was following an old Kodak patent (EP0678783A1) and apparently adding some silver salt to the bleach could speed up the bleaching.

Thanks for the patent number. That is a _super_ interesting patent. Knowing that existed I did some searching this morning and found a few others that I am now reading.

How long did you need to bleach this? Was it at room temperature, or hotter? It's a pretty heavy duty amount of hydrogen peroxide and citric acid in comparison to the bleach I'm working with. Much closer to what the folks were doing with reversal prints.

The research report I shared earlier says that 1% sulphuric acid is the catalyst used in their experiments on peracetic acid synthesis from peroxide and acetic acid. If one wants to get 1% sulphuric acid without having to deal directly with sulphuric acid, ~40g/l of sodium/potassium hydrogen sulphate can be used.

It is unlikely that Fompan 100R emulsion is the source of low amounts of sulphuric acid in your experiments.

Yes, I read that, thanks! Very useful. I had also seen previously that in addition to sulphuric acid, nitric acid and hydrochloric acids can also catalyze it. But I also read that silver is a strong catalyst for the breakdown of hydrogen peroxide. This is actually used in rocket engines. With an aggressive breakdown of peroxide in the presence of a lot of small silver particles—releasing the free oxygen into solution—how much of that oxygen then reacts with the acetic acid? Surely some if it forms peracetic acid. That then may be enough? That's my thinking. Just a theory, probably wrong since I'm not a chemist. @falotico any thoughts on that?

The other option is that it has absolutely nothing to do with peracetic acid at all and something is just supercharging the oxidation rate. I am reading a patent now that I found because of that patent mentioned by @kentanghk that talks about halide ions being an accelerator: https://patents.google.com/patent/US5547816A/en

"According to the present invention there is provided a photographic bleach solution comprising hydrogen peroxide, or a compound which releases hydrogen peroxide, and halide ions and which has a pH in the range of 5 to 11, preferably 5 to 10.


The halide ions are preferably chloride. The time of treatment in the present bleach solution is preferably more than 20 seconds, especially in the range 20 to 40 seconds. Thus the preferred time of treatment in the bleach bath is in the range 20 to 40 seconds."

I do not know how any chloride would have survived the developer in Fomapan R100. But maybe the silver acetate is somehow involved here?


In any case, I will try to find some more time to experiment. Running out of holiday


An update on my last roll with the V3 process. After drying down, it's clear that maximum density is much worse and minimum looks only slightly better. It's not worth the tradeoff. I don't think there is enough silver in this film to run any thiosulfate in the first developer. Might be time to break out the Silvermax for a test. First without any thiosulfate as a benchmark.

 

[falotico]

The release of O2 gas provides a powerful oxidizing agent in the mix which can cause the oxidation of the acetate ions to peracetic acid. This may take time so letting the solution sit overnight probably does increase the concentration of peracetic acid. All an oxidizing agent does is remove an electron, (or more than one), from a chemical. To form peracetic acid from acetate the acetate is oxidized so it will combine with the free O2 to form peracetic acid: O2 + CH3CO2H => CH3CO3H (not a balanced equation). There are probably plenty of halide ions around from trace amounts of the silver halide crystals AgCl, AgI, and AgBr, as well as common salts formed from trace amounts of Na and K ions. Also the O2 could have oxidized leftover halide ions like Cl- into free gas Cl2 which becomes trapped in the gelatin.

The reversals that relistan has posted look wonderful.

 

[kentanghk]

Thanks for the patent number. That is a _super_ interesting patent. Knowing that existed I did some searching this morning and found a few others that I am now reading.

How long did you need to bleach this? Was it at room temperature, or hotter? It's a pretty heavy duty amount of hydrogen peroxide and citric acid in comparison to the bleach I'm working with. Much closer to what the folks were doing with reversal prints.

I bleach for 10min at 38C but it was probably overkill.

 

[ludwighagelstein]

No, dithionite is not a toner like thiourea. It reduces the halides to silver like a regular film developer and not silver sulfide like thiourea toner. You can bleach a dithionite reduced silver image back to halide and redevelop which you can't do with a thiourea reduced image. Also I've not observed dithionite producing distinctly warm tone on the films I've tried. In contrast thiourea toner gives a range of warm tone based on pH and concentration on these very same films.

that´s the reason why ferricyanide bleaches dont work for bw reversal but work for color reversal.

 

[relistan]

The release of O2 gas provides a powerful oxidizing agent in the mix which can cause the oxidation of the acetate ions to peracetic acid. This may take time so letting the solution sit overnight probably does increase the concentration of peracetic acid. All an oxidizing agent does is remove an electron, (or more than one), from a chemical. To form peracetic acid from acetate the acetate is oxidized so it will combine with the free O2 to form peracetic acid: O2 + CH3CO2H => CH3CO3H (not a balanced equation). There are probably plenty of halide ions around from trace amounts of the silver halide crystals AgCl, AgI, and AgBr, as well as common salts formed from trace amounts of Na and K ions. Also the O2 could have oxidized leftover halide ions like Cl- into free gas Cl2 which becomes trapped in the gelatin.

This makes sense! Thanks for the explanation.

The reversals that relistan has posted look wonderful.

Thank you!

I bleach for 10min at 38C but it was probably overkill.

Well it doesn't seem to have removed the image, so it's not massively too much. Thanks!

that´s the reason why ferricyanide bleaches dont work for bw reversal but work for color reversal.

I understood that ferricyanide will (in theory) work for B&W reversal with ammonia as a second step. I think copper sulfate is also used this way? There is a thread about it going on now.

 

[relistan]

Well, I have another not great result to report. After so much early success the last few attempts have been not great. I have had, kind of ironically, very good luck reversing Fomapan 400. That just works, and it also doesn't need anything fancy in the first developer. Maximum density is not amazing, but it is reasonably OK to my eye. If I had a densitometer I would report on it. I would say it's not ideal, but if you are looking for a film to reverse and want to use the simplest possible process, this is your film.

Fomapan R100 was not working at all so far, and I just tried Adox Silvermax (Scala 160, same film) and got a not good result at all. Better than R100 but very bad.

Silvermax 100/Scala 160 test:

• First developer as before (Multigrade 1+5), no thiosulfate, to establish a baseline. Freshly mixed. 10 mins @ 20C
• Second developer as before (Multigrade 1+9), freshly mixed, 6 mins @ 20C
  
• Bleach as before 300ml hydrogen peroxide, 21ml distilled malt vinegar, freshly mixed

I followed the normal process, but when it came to bleaching, the film triggered a pretty aggressive reaction. Not as strong as Fomapan R100, but pretty fizzy. I was running it by inspection so I could see what happened. I agitated some to try to slow the reaction down. That was not really successful. Stupidly, I forgot to wash before re-exposure, so some of the result is probably due in part to that.

It seems the films with more silver are not compatible with this bleach without something to slow it down. See below image. I may try to make it more alkaline by adding some carbonate and see if that helps. Probably will only run one more section of Silvermax, I don't want to waste this nice and expensive film.

Results:

• Got yellow stain all over, appears taht fast bleaching is the cause, as hypothesized by @Raghu Kuvempunagar earlier.
  
• Emulsion damage with pinholes throughout
• VERY good maximum density, almost impenetrable to light it looks like. If I hold it in front of a light bulb and put my finger behind it, I can only barely make out the outline.
  
• Whole film is very dark, definitely needs sodium thiosulfate in the first developer

Not sure this bleach, *freshly mixed* is compatible with this film at all. Will make one more attempt with a more alkaline bleach. Maybe citric acid is more compatible since no peracetic acid forms.

Close up scan of the result. See emulsion damage and staining.

 

[Donald Qualls]

that´s the reason why ferricyanide bleaches dont work for bw reversal but work for color reversal.

Have you actually tested it? It's well known that ferri bleaches, well, bleach the halide back to a developable state. The only remaining question is selective removal of the bleach-generated halide, while leaving the original halide. This requires producing a species that's not originally present in the emulsion, with different solubility from the original bromo-iodide, and then using a suitable solvent.

 

[ludwighagelstein]

Have you actually tested it? It's well known that ferri bleaches, well, bleach the halide back to a developable state. The only remaining question is selective removal of the bleach-generated halide, while leaving the original halide. This requires producing a species that's not originally present in the emulsion, with different solubility from the original bromo-iodide, and then using a suitable solvent.

I actually tried it yesterday, so yes. You get solarized negatives since there´s no way to selectively remove the bleach oxidized halides other than fixer, which would remove all halides.

 

[relistan]

Thinking about the Silvermax 100 issue a bit harder, I don't think what I'm seeing is emulsion damage there. I think that's inadequate bleaching by me rushing it. I think that emulsion damage would be white spots, not dark spots. It's a positive not a negative. So those must be deposits or crystals of some kind. To slow things down, rather than adjusting other factors, I'm going to run it at 15C since that's the current room temperature in my dark room. That ought to slow it down substantially, so hopefully preventing yellow staining, and then let it run for much longer.

 

[Raghu Kuvempunagar]

To slow things down, rather than adjusting other factors, I'm going to run it at 15C since that's the current room temperature in my dark room. That ought to slow it down substantially, so hopefully preventing yellow staining, and then let it run for much longer.

Wouldn't diluting the bleach slow it down?

 

[relistan]

Wouldn't diluting the bleach slow it down?

You are right, yes. But then if I got it wrong, I'd have to make a new batch and I'm low on peroxide. Temperature I can easily vary up and down.

I did run another Silvermax test and I got decent images, and full bleaching. However the black spots remain, as does the yellow/gold/green staining. This was run at 15C for 15 minutes in the dark, so speed of bleaching has nothing to do with it, apparently.

I am no longer sure what is causing the staining. I tried long rinses between steps, running the whole thing in the dark, bleaching slowly. Same outcome. The first few rolls I did had no staining. I tried fresh bleach but got staining. I tried new developers from scratch, got staining. Temperature, time, don't seem to matter. And then there are the black spots on the Silvermax...

I will give a little time to it tomorrow and then I may shelve this for awhile.

Anyone have any other theories about the staining or black spots? Help appreciated.

 

[Raghu Kuvempunagar]

Are you certain that the black spots are not silver that was not oxidised fully by the bleach?

 

[relistan]

Are you certain that the black spots are not silver that was not oxidised fully by the bleach?

It's possible. I can test by clipping off one of the frames and bleaching again to see if they go away (with the rest of the image).

 

[relistan]

Update: it all bleached out. So... maybe still not long enough in the bleach. But this dissolved after fixation, so it doesn't quite prove it yet.