B&W Reversal with Hydrogen Peroxide

[relistan]

This is going to be my final wrap-up on this work for now.

I ran one more section of ADOX Silvermax with about 5 frames on it. I did everything I know how to do to make it go well. I ran it at 20C for 18 minutes, in the dark. I used a 25g/L sodium metabisulfite clearing bath for 3 minutes. I washed extensively between each step. I got emulsion damage and yellow/gold/green staining. They look good to the naked eye, but with a loupe I could see what appeared to be bubbles in the emulsion when whet. As the film is drying, they are turning into the dark spots seen previously.

Conclusions:

• This bleach (peroxide/acetic acid) is not a good general purpose bleach and only works for some films. It's pretty unpredictable in terms of times and it has a mode where it can really set off a quick reaction with lots of bubbles and one where it happens slowly. I have not yet figured out a way to know. Temperature seems irrelevant most of the time but hotter is usually quicker, even for the slower reaction. The fast reaction seems to produce worse results. Presumably the difference here is if peracetic acid is active or not.
• Peroxide bleach seems totally incompatible with Fomapan R100. Even bare peroxide.
• ADOX Silvermax appears incompatible with peroxide/acetic acid bleach
  
• Fomapan 400, ironically the first film I tried, reverses in this bleach very well, and you can do it by inspection because if bleached long enough it seems to produce nice, clear slides. being able to do it by inspection means the unpredictable nature of the bleach is not a big deal. Bonus, the first developer doesn't need thiosulfate and can be re-used for this film.
• There is sometimes yellow staining, sometimes not. At first I had none, then even with fresh bleach it was happening every time. The stain is not attractive to me.
  
• I got some good times for _developers_ for a couple of films and can re-use those with a different bleach
• Ilford Multigrade makes a nice reversal developer and it's easy to get ahold of and reasonably priced
• I now know how to reliably test times and thiosulfate mix for new films. I will write that up somewhere
• Percarbonate bleach (I tried actual percarbonate, not just the stain remover) needs to run too hot and for too long to work without an accelerator. You need appear to need to make it acidic to fully bleach the film and all the sodium carbonate present makes that not really reasonable. There might be better approaches but I didn't try too hard.
  
  That's it for now.

 

[Raghu Kuvempunagar]

It is inevitable that oxygen gas is released by the action of peroxide on silver. The gas is formed inside the emulsion and has to pass through the gelatin to come out. So the risk of the gas creating pinholes in the gelatin while escaping from it is always there.

 

[relistan]

It is inevitable that oxygen gas is released by the action of peroxide on silver. The gas is formed inside the emulsion and has to pass through the gelatin to come out. So the risk of the gas creating pinholes in the gelatin while escaping from it is always there.

Yes, but how does permanganate not have this problem? My guess is that it's slower and gives the oxygen more opportunity to be released without damage.

 

[kentanghk]

Adding some sort of stabiliser to the bleach might prevent staining and emulsion damage imho. I read in several sources that citric acid and phthalic acid can stabilise hydrogen peroxide so it might be worth trying. I may run some tests myself when I get some more hydrogen peroxide.

 

[kentanghk]

Yes, but how does permanganate not have this problem? My guess is that it's slower and gives the oxygen more opportunity to be released without damage.

The reduction of permanganate does not produce oxygen gas so it is not a problem.

 

[relistan]

The reduction of permanganate does not produce oxygen gas so it is not a problem.

I see, I thought the reaction also released oxygen. That explains that.

Adding some sort of stabiliser to the bleach might prevent staining and emulsion damage imho. I read in several sources that citric acid and phthalic acid can stabilise hydrogen peroxide so it might be worth trying. I may run some tests myself when I get some more hydrogen peroxide.

Did you have no staining with your citric acid bleach version ? The reports I've seen with citric acid definitely have a yellow cast. But I'd be all for seeing the results of any testing you can manage. I don't know of anyone trying both acetic and citric acids at the same time so that would be new.

 

[relistan]

On trying to look for a reaction that doesn't form peracetic acid... Someone who knows chemistry better than me like @falotico, @Raghu Kuvempunagar, @kentanghk could weigh in here... but what about trying to form silver carbonate first, then using a separate acetic acid bath to reduce to silver acetate, then washing to remove that? (don't get it near ammonia!) Obviously one more step than bleach/clear.

Would this reaction or something like it even take place? If it did, would it be at a reasonable temperature? (Assumes breakdown of peroxide or percarbonate releasing O2).

2 H2O + 2 Na2CO3 + 4 Ag + O2 = 2 Ag2CO3 + 4 NaOH

 

[kentanghk]

Did you have no staining with your citric acid bleach version ? The reports I've seen with citric acid definitely have a yellow cast. But I'd be all for seeing the results of any testing you can manage. I don't know of anyone trying both acetic and citric acids at the same time so that would be new.

I checked my reversal and apparently there is only minimal staining and emulsion damage. Beginner's luck maybe
It's getting hard to buy hydrogen peroxide here in Hong Kong. Maybe I will get some percarbonate detergent to try instead.

 

[relistan]

I checked my reversal and apparently there is only minimal staining and emulsion damage. Beginner's luck maybe
It's getting hard to buy hydrogen peroxide here in Hong Kong. Maybe I will get some percarbonate detergent to try instead.

Those look great. That stain color is much better than the sort of green/yellow I am seeing. I would be fine with that! I've started to wonder if what I am seeing is chromium getting stripped off my Nikor 35mm film reels. They appear not to be stainless. That might be why I didn't see it at first.

 

[relistan]

Well, Fomapan 400 works really, really well with this bleach. My daughter shot a roll yesterday and we developed it as a reversal. Here's the results. This is a gray as heck Irish morning in January, so keep in mind the backlight from the sky is pretty minimal. But I put it up there with a color backdrop to show that we got no staining, very good highlights, and very good blacks.

This is:

• Fomapan 400 at EI400
• First developer: Ilford Multigrade 1+5, no solvent, 12 minutes @ 20C
  
• Second developer: Ilford Multigrade 1+9, 8 minutes @ 20C
• Bleach: Week old bleach 300ml/21ml, 4 mins @ 40C

Another weird thing to report: After sitting in the window for 2 days, because I left it hanging to dry and was annoyed and didn't take it down, the ADOX Silvermax has _lost_ the staining. I don't know if it was the heat from the radiator, the UV light or what. I've now hung another stained roll there to see what happens.

 

[YoIaMoNwater]

Well, Fomapan 400 works really, really well with this bleach. My daughter shot a roll yesterday and we developed it as a reversal. Here's the results. This is a gray as heck Irish morning in January, so keep in mind the backlight from the sky is pretty minimal. But I put it up there with a color backdrop to show that we got no staining, very good highlights, and very good blacks.

View attachment 262775

This is:

• Fomapan 400 at EI400
• First developer: Ilford Multigrade 1+5, no solvent, 12 minutes @ 20C
  
• Second developer: Ilford Multigrade 1+9, 8 minutes @ 20C
• Bleach: Week old bleach 300ml/21ml, 4 mins @ 40C

Another weird thing to report: After sitting in the window for 2 days, because I left it hanging to dry and was annoyed and didn't take it down, the ADOX Silvermax has _lost_ the staining. I don't know if it was the heat from the radiator, the UV light or what. I've now hung another stained roll there to see what happens.

Hey they look really nice! Yea I noticed Fomapan 400 works great for reversal processing when I was using a depleted Microphen to optimize a reversal protocol. I'm glad you got the peroxide bleach to work. Would be interested to see how other films behave (i.e. Tmax, TriX, Rollei, etc). I would stick to your current method and just change the film stock as the only parameter. Obviously this is only a suggestion, so please proceed if you have time/and are interested in testing it.

 

[relistan]

Hey they look really nice! Yea I noticed Fomapan 400 works great for reversal processing when I was using a depleted Microphen to optimize a reversal protocol. I'm glad you got the peroxide bleach to work. Would be interested to see how other films behave (i.e. Tmax, TriX, Rollei, etc). I would stick to your current method and just change the film stock as the only parameter. Obviously this is only a suggestion, so please proceed if you have time/and are interested in testing it.

Thanks! Yes, this film works super well.

I did try ADOX Silvermax but got blistering in the emulsion and discoloration with this bleach. I actually put quite a bit of effort into getting it working, but it was a no-go. I'm looking into alternative peroxide formulations, like the one that @kentanghk used and some others, to see if one of those works better with Silvermax 100/Scala 160. I have one roll of Rollei Superpan 200 in 120, I may try that with the same times and developers that work for Fomapan 400 and see how that works. I am back to work on Monday so it may be a week before I get much done.

 

[falotico]

Another weird thing to report: After sitting in the window for 2 days, because I left it hanging to dry and was annoyed and didn't take it down, the ADOX Silvermax has _lost_ the staining. I don't know if it was the heat from the radiator, the UV light or what. I've now hung another stained roll there to see what happens.

Beautiful photographs!

It occurs to me that the staining you have been noticing might be from Carey Lea silver which has been produced from the organic ions present in the vinegar. Since you need an acid, vinegar has been added to the bleaching solution. It is believed that the acetate ions are changed into peracetic acid ions which oxidize the Ag grains. In turn the Ag ions become soluble in the mix and can be washed out so that they no longer form the image.

However vinegar contains other junk in it and these organic molecules might form colored silver metal deposits or colored silver halide deposits which cause the stain. Carey Lea was able to make many different colors of silver chloride by precipitating it with organic acids. In his case he used citric acid. Vinegar might contain citric acid--I haven't checked yet. That along with the halide atoms from the silver salts might give you a deposit of colored Carey Lea "photo silver chloride". Such a material would be light sensitive and would turn dark upon exposure to UV rays.

But vinegar probably contains over a hundred trace organic compounds. Who knows what you're getting? You might try using reagent grade acetic acid and see if the pure stuff avoids leaving a stain.

As to why this particular film stock gives such clean results, you have to remember that consumer films can contain over three thousand different chemicals in them. Any combination of them can aid in the reversal process. They would be specific to the film type.

 

[Raghu Kuvempunagar]

I did try ADOX Silvermax but got blistering in the emulsion and discoloration with this bleach.

It occurs to me that the staining you have been noticing might be from Carey Lea silver which has been produced from the organic ions present in the vinegar.

@falotico @relistan: Does Adox Silvermax have Carey-Lea silver layer?

 

[Raghu Kuvempunagar]

one that @kentanghk used and some others, to see if one of those works better with Silvermax 100/Scala 160.

That specific bleach formulation used silver nitrate IIRC. Handling silver nitrate directly might not go well with your stated goal of "cleaner and safer ways to handle the bleach stage of B&W reversal processing". However, there are some low concentration peroxide solutions available in the market that come with some silver nitrate in them. Such peroxide-silver nitrate concoctions might be worth checking out if only very small amount of silver nitrate is sufficient for stabilizing the bleach.

 

[relistan]

Beautiful photographs!

Thanks! Enjoying getting this working well.

It occurs to me that the staining you have been noticing might be from Carey Lea silver which has been produced from the organic ions present in the vinegar. Since you need an acid, vinegar has been added to the bleaching solution. It is believed that the acetate ions are changed into peracetic acid ions which oxidize the Ag grains. In turn the Ag ions become soluble in the mix and can be washed out so that they no longer form the image.

However vinegar contains other junk in it and these organic molecules might form colored silver metal deposits or colored silver halide deposits which cause the stain. Carey Lea was able to make many different colors of silver chloride by precipitating it with organic acids. In his case he used citric acid. Vinegar might contain citric acid--I haven't checked yet. That along with the halide atoms from the silver salts might give you a deposit of colored Carey Lea "photo silver chloride". Such a material would be light sensitive and would turn dark upon exposure to UV rays.

I think this is pretty likely to be one of the things happening. Wouldn't Carey Lea silver have fixed out in the final fix bath? But maybe there was still some it left. But that funky color from the Silvermax is different than the staining I got from other film so it may be that it actually contains a layer of silver intended to behave this way like @Raghu Kuvempunagar mentions.

But vinegar probably contains over a hundred trace organic compounds. Who knows what you're getting? You might try using reagent grade acetic acid and see if the pure stuff avoids leaving a stain.

Yeah, was also thinking this because @YoIaMoNwater previously mentioned silver used for protein staining leaves a brown stain.

As to why this particular film stock gives such clean results, you have to remember that consumer films can contain over three thousand different chemicals in them. Any combination of them can aid in the reversal process. They would be specific to the film type.

Yeah, and I think the "soft" emulsion that some people complain about with the Foma films might also be one reason why it doesn't blister badly.

 

[relistan]

That specific bleach formulation used silver nitrate IIRC. Handling silver nitrate directly might not go well with your stated goal of "cleaner and safer ways to handle the bleach stage of B&W reversal processing". However, there are some low concentration peroxide solutions available in the market that come with some silver nitrate in them. Such peroxide-silver nitrate concoctions might be worth checking out if only very small amount of silver nitrate is sufficient for stabilizing the bleach.

Yes, that's true, but the patent specifies a bunch of different salts that can be used. I will look for one that is pretty clean. If not, then that's a good idea also.

 

[kentanghk]

Yes, that's true, but the patent specifies a bunch of different salts that can be used. I will look for one that is pretty clean. If not, then that's a good idea also.

I wonder if the bleach would still work in the absence of silver nitrate. The patent states that even insoluble silver salt could speed up bleaching and maybe a bleach with silver oxide/ halide would be safer to handle?

 

[Raghu Kuvempunagar]

The patent states that even insoluble silver salt could speed up bleaching

If you are going to use an insoluble salt, wouldn't its particles damage the emulsion during agitation and also form slime on the surface of the film?

 

[kentanghk]

If you are going to use an insoluble salt, wouldn't its particles damage the emulsion during agitation and also form slime on the surface of the film?

Well I guess we'll never know until we run some tests on it.
Also I found another bleach formula in the patent that looks promising:

Bleach C
Hydrogen peroxide 0.980mol/l
phthalic acid monopotassium salt 0.035mol/l
water to 1 liter
pH adjusted to 5.0 with NaOH

I think I have a bottle of potassium hydrogen phthalate somewhere and I will do some test on this formula when I find it.

 

[Raghu Kuvempunagar]

Wouldn't Carey Lea silver have fixed out in the final fix bath? But maybe there was still some it left. But that funky color from the Silvermax is different than the staining I got from other film so it may be that it actually contains a layer of silver intended to behave this way like @Raghu Kuvempunagar mentions.

I could be wrong but I don't think Silvermax/Scala has Carey-Lea silver layer. AFAIK this film can also be developed as a negative and if there were Carey-Lea silver layer, you would get a dense negative like the ones you get when C41 film is developed in B&W chemistry. Fixer will not remove it. OP got stain with Silvermax film and, @falotico, I seriously doubt if it was due to the non-existent Carey-Lea layer. OTOH Fomapan 100R does have a silver layer and hence can't be developed as a negative, at least in a straight forward way.

 

[Lachlan Young]

Those look great. That stain color is much better than the sort of green/yellow I am seeing. I would be fine with that! I've started to wonder if what I am seeing is chromium getting stripped off my Nikor 35mm film reels. They appear not to be stainless. That might be why I didn't see it at first.

You'll damage even 316 stainless with repeated exposure to various photo process bleaches - it's discussed in the Kodak colour process manuals relating to process equipment design.

I could be wrong but I don't think Silvermax/Scala has Carey-Lea silver layer.

Silvermax 100/ Scala 160 has no CLS layer whatsoever. The CLS layer is because of less effective anti-halation technology available to Foma, whereas Agfa/ Adox/ Inoviscoat and the other major manufacturers have long experience in making highly effective anti-hal layers in C-41 and E-6 etc films - all of which are coated on clear bases.

 

[Lachlan Young]

Well I guess we'll never know until we run some tests on it.
Also I found another bleach formula in the patent that looks promising:



I think I have a bottle of potassium hydrogen phthalate somewhere and I will do some test on this formula when I find it.

Bear in mind that while these patents do exist (and Agfa also patented similar), they use a worryingly strong concentration of peroxide - and the effective resolution of the acidified permanganate bleach issues (via manganese sequestration) seems to have resolved the desire to move away from dichromate bleaches with less potential need to reformulate films with more aggressive hardening regimes to counteract vesiculation in materials that hadn't undergone BVSME hardening.

 

[relistan]

I wonder if the bleach would still work in the absence of silver nitrate. The patent states that even insoluble silver salt could speed up bleaching and maybe a bleach with silver oxide/ halide would be safer to handle?

Yeah, this is what I was referring to earlier. It doesn't have to be silver nitrate according to the patent.

Well I guess we'll never know until we run some tests on it.
Also I found another bleach formula in the patent that looks promising:
I think I have a bottle of potassium hydrogen phthalate somewhere and I will do some test on this formula when I find it.

Definitely let us know how it goes. If I recall, that is the preferred incarnation in the patent.

You'll damage even 316 stainless with repeated exposure to various photo process bleaches - it's discussed in the Kodak colour process manuals relating to process equipment design.

Yeah, I had come to the conclusion that I ought to really use my plastic reels/tank, understanding they will probably end up stained.

Silvermax 100/ Scala 160 has no CLS layer whatsoever. The CLS layer is because of less effective anti-halation technology available to Foma, whereas Agfa/ Adox/ Inoviscoat and the other major manufacturers have long experience in making highly effective anti-hal layers in C-41 and E-6 etc films - all of which are coated on clear bases.

I see, that silver anti-halation layer on the Fomapan R100 that dissolves in the bleach like crazy is a Carey Lea silver layer on the backing. That helps tie things together for me. Yeah, Silvermax I normally use as a negative film, obviously, now that I know what folks were referring to in the CLS layer: it definitely does not have one. But the effect is still possible with any silver as far as I understand. So highlights could have a CLS effect as I understand it.

Bear in mind that while these patents do exist (and Agfa also patented similar), they use a worryingly strong concentration of peroxide - and the effective resolution of the acidified permanganate bleach issues (via manganese sequestration) seems to have resolved the desire to move away from dichromate bleaches with less potential need to reformulate films with more aggressive hardening regimes to counteract vesiculation in materials that hadn't undergone BVSME hardening.

It is a good precaution. However, they use 30% hydrogen peroxide but if you read it carefully, all the bleaches use it diluted 9:1. You should be able to use 3% household stuff instead.

Experience so far is that the film I've used with the _softest_ emulsion (Fomapan 400) seems to be the one that works best, with essentially no visible damage in scans. Silvermax, a much more modern and better designed film, ends up with noticeable holes that appear as dark spots. The Kodak patent that @kentanghk is referring to (1995) claims that this invention prevents the emulsion damage of earlier bleaches. One goal is to find out if this is true.

 

[falotico]

I could be wrong but I don't think Silvermax/Scala has Carey-Lea silver layer. AFAIK this film can also be developed as a negative and if there were Carey-Lea silver layer, you would get a dense negative like the ones you get when C41 film is developed in B&W chemistry. Fixer will not remove it. OP got stain with Silvermax film and, @falotico, I seriously doubt if it was due to the non-existent Carey-Lea layer. OTOH Fomapan 100R does have a silver layer and hence can't be developed as a negative, at least in a straight forward way.

I didn't mean to suggest that this film was designed to include a Carey Lea layer of silver composition as part of its normal usage. No, I'm saying that the chemistry of the bleaching reaction will produce entirely new chemicals that didn't exist in the film when the film was manufactured. Basically the bleaching recipe might cause you to synthesize a new chemical--Carey Lea silver--where it did not exist in the original emulsion. That might be causing the stain.

Carey Lea silver is an ambiguous term and it might be causing some confusion. Prof. Carey Lea--who died in the 1890s--studied silver halide light sensitive salts. He was able to produce forms of silver bromide, silver iodide and silver chloride which had distinct colors. Some Carey Lea silver was red, some yellow, some blue, etc.

In addition, some Carey Lea silver did not contain halides, (bromide, iodide, chloride) but was formed out of pure silver metal. Prof. Carey Lea was able to form emulsions of pure silver metal whose grains were so small that they would refract light and cause the emulsion to have a color. The most popular color was/is yellow.

Yellow Carey Lea silver is widely used today. This is the form that contains pure metal silver. Mainly it is used as a colored light filter layer in color film products. Color film has to be sensitive to the three colors of light which the human eye can see: blue light; green light; and red light. The film is manufactured with a layer of silver halide which is sensitive to each of these three colors, blue, green and red. However any silver halide that is used in color film will always be sensitive to blue light .So you get three layers that are sensitive to these colors of light: blue sensitive; blue and green sensitive; blue and red sensitive. The green layer has to be sensitive to green light alone and the red layer has to be sensitive to red light alone. To do this the blue light has to be filtered out before it reaches the green layer and the red layer. So a colored light filter layer is included in the film right behind the blue layer. This light filter layer filters out the blue light after it has exposed the blue layer, but before it exposes the green layer or the red layer.

This light filter layer has to be yellow in color since yellow materials absorb blue light. Some color processes used dyes and some used yellow colored pieces of glass. In modern film they almost always use yellow colored Carey Lea silver which is made out of metallic silver. So behind the blue sensitive layer is a layer of Carey Lea silver which is yellow in color.

Carey Lea silver is used because it is made out of silver metal. Since all of the silver metal is going to bleached out of the film anyway, this filter layer will be bleached out in the normal processing of the film. So you don't need a separate process step to get rid of the yellow light filter layer.

Usually when we use the term "Carey Lea Silver" we mean this light filter layer which is found in most color films. I'm using it generically to refer to silver compounds which have a color. I think some might have been formed in this peroxide bleach method. I didn't mean to suggest that black and white film would contain a light filter Carey Lea layer which is specific to color film.

If Carey Lea silver is formed by accident in the H2O2 bleach method it might have lower solubility than normal silver halides and thus not be washed out when you fix the film.