Copper Sulphate B&W Reversal Bleach

relistan · Feb 27, 2023

MCB18 said:
Alright, cool. I have a list of stuff I need, now I just need to get ammonia and copper sulphate. Ace Hardware has 10% clear ammonia, and copper sulphate as drain cleaner. A gallon of that should last a good long time, giving me 16 liters of 2.5% solution at least, and 2 lbs of copper sulfate should make lots of bleach, and probably some big crystals, too.

That sounds good. I have household ammonia and copper sulfate (root killer) from the hardware store. Let us know how it goes!

MCB18 · Mar 15, 2023

ok, progress!

Developed negative

Redeveloped positive

Not sure what I did, but I think I might not have bleached it long enough, or i underexposed the original picture.

relistan · Mar 15, 2023

MCB18 said:
ok, progress!
View attachment 332572
Developed negative

View attachment 332573
Redeveloped positive

Not sure what I did, but I think I might not have bleached it long enough, or i underexposed the original picture.

Hey a first step. Looks under-developed and possibly under-exposed and under-bleached to me. But headed in the right direction.

To test bleaching and first development time, I suggest that you blacken down a small strip of film with full light exposure. Then develop and bleach and fix. Repeat, changing dev time or solvency of your first developer and bleach time until you get a clear strip.

Once you have that working, I suggest shooting five frames of 35mm at a time while getting your full process going. -2, -1, box speed, +1, +2. That way you can find the right speed for your process more easily and get a better hint as to what you need to adjust. Because the blackened film strip is only a starting point.

Once that works, scale up to 120 or more expensive film sizes.

MCB18 · Mar 15, 2023

relistan said:
Hey a first step. Looks under-developed and possibly under-exposed and under-bleached to me. But headed in the right direction.

To test bleaching and first development time, I suggest that you blacken down a small strip of film with full light exposure. Then develop and bleach and fix. Repeat, changing dev time or solvency of your first developer and bleach time until you get a clear strip.

Once you have that working, I suggest shooting five frames of 35mm at a time while getting your full process going. -2, -1, box speed, +1, +2. That way you can find the right speed for your process more easily and get a better hint as to what you need to adjust. Because the blackened film strip is only a starting point.

Once that works, scale up to 120 or more expensive film sizes.

Yeah, I think I under-deved the original negative, and quite possibly underexposed the negative.
As for testing, the only B&W film I have is a bulk roll of Aviphot 200, lol. So that’s what I’m testing with.

Donald Qualls · Mar 15, 2023

When I've done B&W reversal (been a while, but I have my notes), I first developed in Dektol 2+1 (two parts stock to one part water) for twelve minutes. I'm pretty sure that's development to completion. I then bleached to completion as well (the bleach removes only developed silver), and the second developer can also be run to completion, since both contrast and overall density are controlled by the first dev. Doing this with early 2000s vintage Tri-X, I got a workable speed of EI 640, but different films will give different results in terms of speed relative to box speed.

Either underexposure or underdevlopment in the first dev will result in dark final slides. if the slide is dark and there's not much separation between lights and darks, it's probably underdeveloped; if the separation is good, but everything is too dark, it's likely underexposed. If you can't be sure which, it's probably both, so start with increasing first development, then adjust exposure in later rolls once you have good separation of values.

MCB18 · Mar 16, 2023

Donald Qualls said:
When I've done B&W reversal (been a while, but I have my notes), I first developed in Dektol 2+1 (two parts stock to one part water) for twelve minutes. I'm pretty sure that's development to completion. I then bleached to completion as well (the bleach removes only developed silver), and the second developer can also be run to completion, since both contrast and overall density are controlled by the first dev. Doing this with early 2000s vintage Tri-X, I got a workable speed of EI 640, but different films will give different results in terms of speed relative to box speed.

Either underexposure or underdevlopment in the first dev will result in dark final slides. if the slide is dark and there's not much separation between lights and darks, it's probably underdeveloped; if the separation is good, but everything is too dark, it's likely underexposed. If you can't be sure which, it's probably both, so start with increasing first development, then adjust exposure in later rolls once you have good separation of values.

Did you found it necessary to add anything to the first dev? Some folks say that you should add a bit of rapid fix, and others say not to. From what I gather, you did this a while ago, so if you’re not sure, I totally understand.

Donald Qualls · Mar 16, 2023

I didn't in these cases, at least according to my notes, though adding a couple grams per liter of plain sodium thiosulfate is an accepted practice to lighten the overall slide or clear the highlights (in the final positive). I've done this once when I developed very old found Kodachrome for B&W slides, and it worked okay. My own preference, if you find this is needed, would be to give a separate bath in, say, 10 g/L sodium thiosulfate after the bleach step. Done by inspection, stopping as soon as the highlight areas are clear enough, this is more controllable than including the halide solvent in the first developer.

MCB18 · Mar 16, 2023

Ahh, ok. I have a sodium sulfite clearing bath after the bleach. I’m not sure if that accomplishes the same thing, but it may.

Also, a silly question, at what point is the film light-safe? Is it good as soon as it’s developed, or is it only safe to take it out after the bleach? I would like to bleach by inspection for the first little bit, but I’m afraid maybe the light could up the results. Thinking about it, I want to say it’s probably fine to take it out and look at it in subdued light after the dev, but I’m not sure.

Bronson Dugnutt · Mar 16, 2023

Excellent advice on this page so far.

Donald Qualls said:
... My own preference, if you find this is needed, would be to give a separate bath in, say, 10 g/L sodium thiosulfate after the bleach step. Done by inspection, stopping as soon as the highlight areas are clear enough, this is more controllable than including the halide solvent in the first developer.

I do this as well; it's an especially useful technique when working with an unknown film/developer combo. You can achieve a similar effect by bleaching & re-fixing the final positive, although that's obviously less than ideal.

Edit:

MCB18 said:
Ahh, ok. I have a sodium sulfite clearing bath after the bleach. I’m not sure if that accomplishes the same thing, but it may.

Also, as a silly question, at what point is the film light-safe? Is it good as soon as it’s developed, or is it only safe to take it out after the bleach? I would like to bleach by inspection for the first little bit, but I’m afraid maybe the light could up the results.

The sulfite presumably acts to neutralize any remaining bleach and prevent staining.

It's light-safe after the stop bath. I always use an acid stop after 1st dev when reversing to ensure no unintentional fogging and do all remaining steps in room light.

MCB18 · Mar 16, 2023

Bronson Dugnutt said:
The sulfite presumably acts to neutralize any remaining bleach and prevent staining.

So if I understand this correctly, it isn’t doing quite the same thing as the sodium thiosulphate. But it will probably work.

All this being said, I wonder how 5222 will work in this process. The base seems to be a bit darker, could that be a problem?

Bronson Dugnutt · Mar 16, 2023

MCB18 said:
So if I understand this correctly, it isn’t doing quite the same thing as the sodium thiosulphate. But it will probably work.

All this being said, I wonder how 5222 will work in this process. The base seems to be a bit darker, could that be a problem?

No, sulfite isn't a replacement for thiosulfate. The sulfite solution is a 'clearing bath' while thiosulfate is a 'fixing bath'. Try not to be confused by the terminology.

Essentially any B&W filmstock can be reversal processed by tuning your process as outlined earlier by @relistan & @Donald Qualls.

As a rule of thumb I'll overexpose by at least one stop, more often two, if I plan on reversal processing a roll. This is not universal, however, as I've found PanF+ needs upwards of 4 stops overexposure in my preferred thiosulfate-less 1st developer process. My go to at the moment is Kentmere 100 as the 'cheapness' of the emulsion works quite well at box speed with no fixing treatment (thiosulfate), similar to Fomapan.

Film base will obviously have an impact on the final positive. Films with perfectly clear bases (e.g. Kodak 2238 et al.) look and project differently than XX. Just think of it as akin to paper choice when printing: glossy, pearl, matte, or hand-coated cotton rag. It's a matter of personal taste unless you've been handed some sort of dictate to produce b&w slides.

Donald Qualls · Mar 16, 2023

Bronson Dugnutt said:
No, sulfite isn't a replacement for thiosulfate. The sulfite solution is a 'clearing bath' while thiosulfate is a 'fixing bath'. Try not to be confused by the terminology.

What the thiosulfate (NOT replaceable by sulfite) does in my method is to allow you to by inspection ensure clear highlights with minimal effect on the Dmax. The option still exists to bleach the finished slides with potassium ferricyanide (don't use Farmer's Reducer; if you go too far with just the ferricyanide you can just redevelop and try again, but go too far with Farmer's, which includes fixer, and you've shot yourself in the foot).

MCB18 · Mar 17, 2023

Has anyone else had issues with the 1+9 working solution taking a really long time to bleach? I am not seeing the highlights turn yellow even after 10+ minutes in the copper sulfate solution. (Previous attempt was accidentally using the full strength solution)

svetoklik · Mar 18, 2023

DarkroomExperimente said:
how much copper sulfate/NaCl ? and for how long...I gotta try this...I loved BW reversal back in the day

1+

relistan · Mar 18, 2023

I don’t agree with some of the advice or explanations above. From my experience:

Using a sodium thiosulfate bath by inspection is going to be super hard to get right vs a determined, tested time in the first developer. You can hardly see what’s going on with frames in the center of the roll, and solvency is not at all uniform across the frame in short times.
You can over develop in the first developer and introduce extra fog, or get very grainy results, which makes the end result worse. The first developer is not development to completion.
A separate thiosulfate bath does not accomplish the same thing as solvent in the first developer. Solvent first developers (with thiosulfate, thiocyanate in very small amounts—way less than 10g/L) also enable development of latent sites that are not as easily reached. This leads to clearer highlights without thinning the whole image as much.
The sulfite clearing bath is to remove the silver citrate left by the bleach and has nothing to do with highlights other than that.

Hope that helps…

relistan · Mar 18, 2023

MCB18 said:
Has anyone else had issues with the 1+9 working solution taking a really long time to bleach? I am not seeing the highlights turn yellow even after 10+ minutes in the copper sulfate solution. (Previous attempt was accidentally using the full strength solution)

Please post exactly which bleach formula you are using.

MCB18 · Mar 18, 2023

relistan said:
Please post exactly which bleach formula you are using.

50g copper sulfate, 50g salt, 10g citric acid, diluted 1+9 to make a working solution.

relistan · Mar 18, 2023

MCB18 said:
50g copper sulfate, 50g salt, 10g citric acid, diluted 1+9 to make a working solution.

Ah, that’s meant to be used full strength, not diluted. I would guess that’s the issue then.

MCB18 · Mar 18, 2023

relistan said:
Ah, that’s meant to be used full strength, not diluted. I would guess that’s the issue then.

Ahhh, I thought it was supposed to be diluted, good to know.

MCB18 · Mar 20, 2023

Quick question regarding first dev, would it be possible to use a small amount of Kodafix in the first developer to lighten the positive? Thanks.

Donald Qualls · Mar 20, 2023

MCB18 said:
Quick question regarding first dev, would it be possible to use a small amount of Kodafix in the first developer to lighten the positive? Thanks.

It's possible, but Kodafix is acidic. This may change your developer pH and result in underdevelopment -- you'd have to test to determine how much time to add.

MCB18 · Mar 20, 2023

Donald Qualls said:
It's possible, but Kodafix is acidic. This may change your developer pH and result in underdevelopment -- you'd have to test to determine how much time to add.

Ahh. Good to know. So I should really only be using hypo powder, not actual fixers.

MCB18 · Mar 21, 2023

Well well well, look what we have here!

Still need to work on first dev (24 mins in Dektol 1+2 LOL), and it could probably do with a stop of over-exposure compared to box speed, but this is my first passable positive!

On a side note, this slide is almost impossible to see unless held up to the light, is this normal?

MattKing · Mar 21, 2023

MCB18 said:
Ahh. Good to know. So I should really only be using hypo powder, not actual fixers.

Assuming "hypo powder" refers to sodium thiosulfate - old name sodium hyposulfate - it probably is acidic also, and it certainly is fixer.

Anon Ymous · Mar 21, 2023

MattKing said:
Assuming "hypo powder" refers to sodium thiosulfate - old name sodium hyposulfate - it probably is acidic also, and it certainly is fixer.

Neutral.

Copper Sulphate B&W Reversal Bleach

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