B&W Reversal with Hydrogen Peroxide

[Raghu Kuvempunagar]

Even claims of speed increase in reversal processing due to a high energy first developer are questionable. While it seems plausible that the lightly sensitized halides in the deep shadows can be rendered developed by a high energy developer, it will invariably be accompanied by increased base fog and thereby reducing DMax of the positive image. So a restrainer is added to the high energy developer which reduces base fog but also voids any gain in speed.

 

[Fragomeni]

Sorry if that was not clear: there is no reduction in speed from the Citric acid/EDT bleach. Fomapan 400 is not a 400 speed film (per Foma's own datasheets), so shooting it at 400 is a ~1 stop increase. Also keep in mind that the developer has much more to do with speed increase than the bleach. However, the bleach can make the speed worse by blixing too much and leaving you with a thin negative. Leaving it in the bleach too long in the acetic acid/peroxide bleach will take quite a lot away. The unpredictable nature of the bleach speed is also very annoying.

Not unclear about the speed you were seeing but thanks making sure. How much more predictable do you find the EDTA version? I understand it’s an improvement but is predictability essentially solved when going that route?

The leftover yellow "staining" from the acetic acid bleach is not actually staining, as discussed earlier in the thread. It's fine grains of silver that get evenly deposited across the film. This is why it doesn't clear with a sulfite bath. The EDTA and citric acid in the the bleach we formulated on this thread chelate that silver and prevent it from re-depositing on the film. You still need to use a sulfite bath with this bleach to get rid of the actual staining.

This is exactly the clarity I was looking for. I knew I read this previously but couldn’t find it for some reason. The chelating effect of EDTA/citric acid preventing the redepositing of the silver makes sense.

In your negatives you are definitely seeing some emulsion damage. But because they are so big you probably don't see it on scans. Do a detailed scan and zoom to the highest resolution and you will definitely see it. Some films do better than others. Temperature seems to have very little impact from all the testing I did. Which is further reinforced by the fact that none of the patents out there talk about temperature as a controlling factor in emulsion damage.

Oh I have no doubt that it’s there under high resolution scans. I only meant what I was seeing looking at the film alone. I haven’t done high res scans yet to take a very close look but considering the action of peracetic acid I’m sure effects are there to some degree.

Yes, we did test it. No it doesn't work well. You get weird swirl lines all over the film.

Thanks for this. I knew it must have been tried.

If the bleach (or an additive in first developer, such as the thiosulfate I've added in the past) dissolves some of the undeveloped halide, this will lighten the final positive -- which is effectively an increase in film speed.

I am pretty sure as I said a few posts back that what you are seeing with speed gain has nothing to do with the bleach and everything to do with the very aggressive developers being used. AFAICT the only thing the bleach can do is to make the positive thinner all around…

It would seem to make sense that both of these explanations are contributing to what’s happening. Yes, developer is for sure going to impact the speed but the action of bleach/thiosulfate on the thinning of undeveloped halide resulting in a lighter final positive makes sense and in the end can really only be considered as an effect on speed. Even if it’s essentially indirectly resulting in the speed increase because of its subtractive action, the end result is still a lighter final positive when means over-exposure/speed gain.

Very interesting and I hadn’t been considering that this was what was happening. Hugely helpful in understanding exactly how the film speed increase is occurring.

 

[Raghu Kuvempunagar]

the action of bleach/thiosulfate on the thinning of undeveloped halide resulting in a lighter final positive makes sense and in the end can really only be considered as an effect on speed. Even if it’s essentially indirectly resulting in the speed increase because of its subtractive action, the end result is still a lighter final positive when means over-exposure/speed gain.

This doesn't seem correct to me. Lightening of the final positive due to Blix action of the bleach is basically a reduction in contrast and not an increase in speed. But we don't need to argue over this as any claim on speed increase can be easily tested by those who make the claim.

 

[Fragomeni]

This doesn't seem correct to me. Lightening of the final positive due to Blix action of the bleach is basically a reduction in contrast and not an increase in speed. But we don't need to argue over this as any claim on speed increase can be easily tested by those who make the claim.

Definitely no intention to argue anything here. The different perspectives in looking at this are all very useful. I’m referring to this lightning effect as an increase in speed from the perspective of how over and under exposure present in reversal positive images. So maybe I’m just interpreting it as an effect on speed when the actual mechanism at play is a thinning in reality. I see the distinction there. I’m just looking at it in terms of how it relates to how I have to treat exposure. As I’m looking at it, if the end result is that I expose for less time, resulting in the appropriate image density where a longer (normal) exposure would have resulted in a lighter blown out image, then to me it’s useful to understand that what’s happening is actually a thinning effect but what it translates to is film speed (at least as far as how I’m going to treat it). Not sure if that makes any useful sense. The explanation of it as a reduction in contrast is more technically correct I think.

 

[Lachlan Young]

Even claims of speed increase in reversal processing due to a high energy first developer are questionable.

Reversal processing is the only process in which a real and measurable speed increase can happen from an extended FD step (of an appropriate type that is able to access and develop all the available silver). The speed increase is (I recollect) however not terribly large - about 1/2 stop or so. The mechanisms are explained elsewhere on here. The problem is that the speed increase comes with a loss of Dmax.

 

[Raghu Kuvempunagar]

Reversal processing is the only process in which a real and measurable speed increase can happen from an extended FD step (of an appropriate type that is able to access and develop all the available silver). The speed increase is (I recollect) however not terribly large - about 1/2 stop or so. The mechanisms are explained elsewhere on here. The problem is that the speed increase comes with a loss of Dmax.

Even that 1/2 stop increase in speed, if and when it happens, can and should be tested and confirmed. Otherwise, the very few who do reversal processing today end up building a web of myths about reversal processing.

 

[Lachlan Young]

Even that 1/2 stop increase in speed, if and when it happens, can and should be tested and confirmed. Otherwise, the very few who do reversal processing today end up building a web of myths about reversal processing.

They are well known within the literature, described by researchers who work with the processes - and obvious from manufacturers' characteristic curves if/ when push & pull effects are shown. If you are not getting these effects then there is something wrong with your process. The myths largely arise from those who don't bother to actually understand the inherent behaviour of the processes involved - and simultaneously fancy themselves cleverer than the photo engineers who designed the materials/ processes in the first place.

 

[Raghu Kuvempunagar]

@Fragomeni: this could be of interest to you and others in this forum who reversal process FP4.

Quoting from the page on reversal processing by a preeminent manufacturer of films, italics mine. I believe the 'our' in the italicized sentence refers to the manufacturer's R&D team.

"For general indoor/outdoor use, first adopt the published ISO setting and vary this, by trial and error, to determine the best exposure for your particular taste. In our tests we found 1 stop over exposed to be a good starting point."
https://www.ilfordphoto.com/reversal-processing/

When you're shooting FP4 at EI:500, you're actually giving nearly 3 stops less exposure than optimal. If processed normally, that would give you very dark positives. You can increase the halide solvent (thiosulphate or thiocyanate) in the first developer and also increase the developing time to get lighter slides. However, the resulting positives will have low contrast and show significant shadow loss. Such slides might not shine when projected but can possibly give acceptable results when scanned and post-processed. If that's acceptable to you then there is nothing wrong in shooting at EI:500.

 

[Fragomeni]

All of the comments made thus far have value as parts of a greater conversation but the key is remembering that each position is just that, a part of a rather complex whole. The best any of us can do is be familiar with the existing literature and test against those known opinions and controls in order to share our results and further learn from everyone’s experiences.

They are well known within the literature, described by researchers who work with the processes - and obvious from manufacturers' characteristic curves if/ when push & pull effects are shown…

I would agree here. The phenomena of speed gain in reversal is well established. It can be explained in any number of different ways but the point remains that under particular conditions, less exposure can be used for an optimal result. The key being who is defining “optimal” and what the user’s end goal is. There is no such thing as a general “correct” anything in reality. The ideal density of a slide, dmax, contrast, etc are all determined by the desired end goal. Everyone finds their own process. Like in any other process, development and subsequent results are different for silver gel vs pt/pl vs scanning vs producing slides for projection vs slides for scanning etc etc. Manufacturer recommendations have always been purely made for acceptable results under a generally accepted set of guidelines and assumed purposes. Step outside of that assumed standard and a new set of ideals must be assumed.

Even that 1/2 stop increase in speed, if and when it happens, can and should be tested and confirmed.

Definitely agree with the testing statement here. The most value any of us can provide is well documented results. Everything should be tested, and then tested again.
1/2 stop is conservative here but again dependent on what one is trying to achieve.

@Fragomeni: this could be of interest to you and others in this forum who reversal process FP4.

Quoting from the page on reversal processing by a preeminent manufacturer of films, italics mine. I believe the 'our' in the italicized sentence refers to the manufacturer's R&D team.

"For general indoor/outdoor use, first adopt the published ISO setting and vary this, by trial and error, to determine the best exposure for your particular taste. In our tests we found 1 stop over exposed to be a good starting point."
https://www.ilfordphoto.com/reversal-processing/

Yes, I’m familiar with the linked documents. The first time I did this that’s actually the recommendation that I followed re: starting off with 1 stop over exposure, but that did not prove useful for me. Perhaps because I’m in an overall warmer climate or because I’ve found that working with warmer temperature solutions for reversal works best for me, the 1-stop over exposure rec hasn’t made its way into my process. It becomes more applicable with shorter less aggressive development times and dilutions as well as cooler solution temperatures but in the end, I’ve stuck with warmer solutions and longer times and am happy with the results. Again, we’re just talking about variations of essentially the same approach tailored to an individuals specific goals (manufacturer recommendations aside).

When you're shooting FP4 at EI:500, you're actually giving nearly 3 stops less exposure than optimal. If processed normally, that would give you very dark positives. You can increase the halide solvent (thiosulphate or thiocyanate) in the first developer and also increase the developing time to get lighter slides. However, the resulting positives will have low contrast and show significant shadow loss. Such slides might not shine when projected but can possibly give acceptable results when scanned and post-processed. If that's acceptable to you then there is nothing wrong in shooting at EI:500.

The key here is that I’m not processing these as normal negatives to make a positive print. That’s a different process altogether with different intended outcomes. This is where speaking to intended outcomes becomes important. Generalizations based on a different process has little practical use here. I’m curious though if you’re basing this on assumptions based on existing literature or are you basing this on your own real life tests? It’s the real life results and testing that moves this conversation along. I made the same set of assumptions and have been both surprised and pleased to find that with my specific process (which deviates significantly from a normal manufacturer recommendation for negative development) I’m not getting particularly thin or overly low contrast slide positives. Now I wouldn’t turn around and try to print these in pt/pl or on AZO paper/silver chloride etc. The density isn’t there for that. But then again, that was never the intended purpose which underlines the overarching point.

 

[Raghu Kuvempunagar]

The key here is that I’m not processing these as normal negatives to make a positive print. That’s a different process altogether with different intended outcomes. This is where speaking to intended outcomes becomes important. Generalizations based on a different process has little practical use here.

The recommendation by Ilford to overexpose by a stop was specifically for reversal processing of their films including FP4+. You can check again the link I shared earlier.

 

[Fragomeni]

The recommendation by Ilford to overexpose by a stop was specifically for reversal processing of their films including FP4+. You can check again the link I shared earlier.

Raghu, you may have missed a paragraph in my previous response. As I said, I am aware of Ilford’s recommendation, that’s exactly what my initial starting point for exposure was based on, and I arrived at a different outcome (because the process I’m using is very different than the one that the Ilford document describes). We’re concerned with hydrogen peroxide reversal here. The Ilford document is not referring to this process. The basis for Ilford’s tests involves permanganate and sulfuric acid as the bleach, which is exactly what hydrogen peroxide bleaching aims to avoid. Further, I’m not using the same developer Ilford used. I do not add sodium thiosulfate to my developer and I use a dilution of 1+9 HC-110 for both first and second development. Also, my agitation, temperatures, and development times are all different. The details of the Ilford document are only useful for general reference here. Outcomes should not be expected to be the same considering the number of variables that differ.
This has become tangential to the topic of the thread so let’s allow the focus to return to findings from actual testing of variations of the peroxide bleaching process.

 

[Raghu Kuvempunagar]

@Fragomeni: English isn't my native tongue and I at times struggle to express my point of view clearly. My mere point was that in reversal processing, bleach doesn't increase the speed of a film nor does the first developer beyond a small increment. If Ilford has recommended giving additional exposure for their films, it's not because they use Permanganate bleach. If you look at major labs doing reversal processing today, DR5 and Studio 13, they too recommend EI <= 125 for FP4+ for best results and DR5 doesn't use Permanganate bleach. It doesn't mean, however, that FP4+ can't be shoot at 250 or 500. One can get acceptable results at higher EI but with significant shadow loss. So, if your process of underexposing FP4+ and bleaching with peroxide has given you acceptable results, it's fine - whatever works for you. I'll desist from commenting further on this topic as I'll be repeating myself to the boredom of many.

 

[Fragomeni]

@Fragomeni: English isn't my native tongue and I at times struggle to express my point of view clearly. My mere point was that in reversal processing, bleach doesn't increase the speed of a film nor does the first developer beyond a small increment. If Ilford has recommended giving additional exposure for their films, it's not because they use Permanganate bleach. If you look at major labs doing reversal processing today, DR5 and Studio 13, they too recommend EI <= 125 for FP4+ for best results and DR5 doesn't use Permanganate bleach. It doesn't mean, however, that FP4+ can't be shoot at 250 or 500. One can get acceptable results at higher EI but with significant shadow loss. So, if your process of underexposing FP4+ and bleaching with peroxide has given you acceptable results, it's fine - whatever works for you. I'll desist from commenting further on this topic as I'll be repeating myself to the boredom of many.

No worries at all on the language thing. I think your posts have been very clear. And yes, I understand what you’ve been saying. The more information we have to compare to our own results the better.

 

[Lachlan Young]

Ilford's recommendation is likely to relate more to ensuring that the available silver is fully accessed for development - which can potentially be done via solvent, accelerator or overexposure.

 

[Fragomeni]

I had the chance to try my hand at the improved reversal formula (EDTA version) with Fomapan 400 in 120. I definitely agree with those who spoke of this combination as particularly valuable because of the transparent film base of Fomapan 400 in 120 size and the more neutral color of slides made with this improved bleach formula. I still see the slightest bit of a gold hue in my slides but a massive improvement over the almost sepia of the vinegar formula (I actually like the sepia tone as well and can see value in both). I still see a speed increase in my results, although this time 1/2 - 1 stop (compared to 2 stops with the vinegar formula. I was surprised to find any increase in speed with this based on the results others have had. Below is a quick exposure comparison (don't mind the light leak on the right edges of each frame -- thats from removing my darkslide with a slight light leak). I'm in Souther California where things are a little warmer so pretty much the only deviation from the formula as written is that my chemistry is at 28C rather than 20C. The example below is just taken with my iphone but it does a decent job of showing the exposure differences. The 0 exposure is a bit washed out where as the -1 exposure is pretty dead on (more so in real life than in this quick phone scan).

 

[Fragomeni]

For those using this process, which of the solutions are you finding can be saved and used more than one shot? I see the bleach referenced as keeping well in brown bottles but is that keeping after being mixed and then using one-shot or keeping and being reused? Also, the sodium sulfite bath, does this keep and can it be reused? My instinct is to use everything one shot to maintain better consistency but am interested in what others have found.

 

[relistan]

I had the chance to try my hand at the improved reversal formula (EDTA version) with Fomapan 400 in 120. I definitely agree with those who spoke of this combination as particularly valuable because of the transparent film base of Fomapan 400 in 120 size and the more neutral color of slides made with this improved bleach formula. I still see the slightest bit of a gold hue in my slides but a massive improvement over the almost sepia of the vinegar formula (I actually like the sepia tone as well and can see value in both). I still see a speed increase in my results, although this time 1/2 - 1 stop (compared to 2 stops with the vinegar formula. I was surprised to find any increase in speed with this based on the results others have had. Below is a quick exposure comparison (don't mind the light leak on the right edges of each frame -- thats from removing my darkslide with a slight light leak). I'm in Souther California where things are a little warmer so pretty much the only deviation from the formula as written is that my chemistry is at 28C rather than 20C. The example below is just taken with my iphone but it does a decent job of showing the exposure differences. The 0 exposure is a bit washed out where as the -1 exposure is pretty dead on (more so in real life than in this quick phone scan).

Sorry for going dark on this thread for a couple of weeks. Was taking a much needed vacation!

Hey, great! Glad it worked out for you. @kentanghk and I spent many, many hours getting to that formula. Looks like you got very good results. And yes, the Fomapan 400 works surprisingly well considering they don't recommend it as a reversal film. Not the best Dmax in the world, but looks good. You say you still have a bit of yellow staining. Did you use the clearing bath?

For those using this process, which of the solutions are you finding can be saved and used more than one shot? I see the bleach referenced as keeping well in brown bottles but is that keeping after being mixed and then using one-shot or keeping and being reused? Also, the sodium sulfite bath, does this keep and can it be reused? My instinct is to use everything one shot to maintain better consistency but am interested in what others have found.

The vinegar stuff lasts for quite awhile. Note that its behavior is quite unpredictable, though, because the amount of peracetic acid formed has a big impact on speed and amount of bleaching. I found that the Citric acid/EDTA bleach will last a month or more and probably 3 rolls of film for 500ml (e.g. guessing maybe 5-6 rolls for 1L). After that it still works, but you get more staining. I never tried to exhaust it. I did let it sit for a few months and then when I went back to it it was not working any more. However, there was a fair bit of air in that particular jar.

If you don't mind one shot you will definitely get the best results.

 

[Fragomeni]

Sorry for going dark on this thread for a couple of weeks. Was taking a much needed vacation!

Hope the vacation was great! I just got back myself and planned to have many rolls to process as b&w reversal...but sure enough left my bag of film on the plane. Too much plane wine I guess.

Glad it worked out for you. @kentanghk and I spent many, many hours getting to that formula. Looks like you got very good results. And yes, the Fomapan 400 works surprisingly well considering they don't recommend it as a reversal film. Not the best Dmax in the world, but looks good.

Yea, the Fomapan is pretty great for this although true about the Dmax. Thats the main thing I wished was a little better but really I'm fine with it. The slides still look great.

You say you still have a bit of yellow staining. Did you use the clearing bath?

Strangely, the yellow stain is only visible on the +2 exposure which doesn't really make sense. I suppose maybe because it's so light you can see it while the other exposures hide it because of their density. It's harder to see in the picture I posted but the +2 exposure has a noticeable yellow cast in real life. The other exposures have the very slightest hint but are otherwise neutral. You have to really look for it in those, not really noticeable for the most part. And yea, I used the clearing back.

The vinegar stuff lasts for quite awhile. Note that its behavior is quite unpredictable, though, because the amount of peracetic acid formed has a big impact on speed and amount of bleaching. I found that the Citric acid/EDTA bleach will last a month or more and probably 3 rolls of film for 500ml (e.g. guessing maybe 5-6 rolls for 1L). After that it still works, but you get more staining. I never tried to exhaust it. I did let it sit for a few months and then when I went back to it it was not working any more. However, there was a fair bit of air in that particular jar.

If you don't mind one shot you will definitely get the best results.

Thanks for this info. Yea, I'll likely just use it one shot for the control factor.

 

[relistan]

Hope the vacation was great! I just got back myself and planned to have many rolls to process as b&w reversal...but sure enough left my bag of film on the plane. Too much plane wine I guess.

It was great, although too short . Oh, no! I hope you were able to recover the film and it's not all gone :|

 

[Fragomeni]

It was great, although too short . Oh, no! I hope you were able to recover the film and it's not all gone :|

Nope. I realized it the moment I passed the checkpoint where you can't turn back so of course I wasn't able to go back and get it. Called American Airlines and sure enough they have no actual system in place other than to fill out an online form. No actual lost and found department or anyone to talk to. Filled out the form and nothing. I wouldn't expect much more from AA though anyway so oh well.

 

[Fragomeni]

Anyone have idea on how to get better Dmax in this reversal process? I’m still holding onto hope that DR5 will eventually release their process as was claimed but hasn’t happened yet. Rich Dmax is about all I long for now.

 

[Raghu Kuvempunagar]

DMax is generally not an issue in reversal processes that use Dichromate or Copper Sulphate bleach in my experience. Of course DR5's DMax is at a different league altogether. BTW DR5 uses Dichromate bleach.

 

[relistan]

Anyone have idea on how to get better Dmax in this reversal process? I’m still holding onto hope that DR5 will eventually release their process as was claimed but hasn’t happened yet. Rich Dmax is about all I long for now.

You get some blixing with the peroxide bleaches. The EDTA/citric acid one is much less of a blix than the vinegar bleach, but still happens. And Fomapan 400 is a thinner emulsion. The thicker emulsions that can produce higher Dmax also don't do well with peroxide bleach because they have more emulsion damage from bubbles of 02 escaping when the peroxide breaks down (catalyzed by silver). So you either get better Dmax or less emulsion damage in my experience. There might be a film out there that is a middle ground, but I haven't yet tested it.

That being said, if your first developer is overly aggressive or contains too much sliver solvent you can cause further loss of Dmax. It's probably the place to look for better Dmax first IMO.

 

[Fragomeni]

DMax is generally not an issue in reversal processes that use Dichromate or Copper Sulphate bleach in my experience. Of course DR5's DMax is at a different league altogether. BTW DR5 uses Dichromate bleach.

Yea, I was thinking about this. Didn’t realize DR5 used dichromate but makes sense. Once they release their details and we know what else is in the secret sauce it’ll be exciting to finally be able to have a complete picture of all reversal modalities to compare. I love the much reduced level of toxicity with this citric acid/ EDTA process but I might be more tolerant of increased toxicity with that level of rich blacks.

That being said, if your first developer is overly aggressive or contains too much sliver solvent you can cause further loss of Dmax. It's probably the place to look for better Dmax first IMO.

Interesting, this makes sense. Solid point. Thanks for this.

 

[YoIaMoNwater]

Anyone have idea on how to get better Dmax in this reversal process? I’m still holding onto hope that DR5 will eventually release their process as was claimed but hasn’t happened yet. Rich Dmax is about all I long for now.

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.