You need more Dektol stock and less water. I used two parts Dektol stock to one part water and 12 minutes, with good results.
Copper Sulphate B&W Reversal Bleach
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You need more Dektol stock and less water. I used two parts Dektol stock to one part water and 12 minutes, with good results.
Hey, good progress. This is nice and lacking in stain and looks quite even. So you are on the right track. Bleach time may be close to right and second developer may be close as well.
I suggest you get a little sodium thiosulfate crystals and add 1g per liter to your first developer. (NOTE do not put this in the second developer). This won’t affect pH noticeably because it’s neutral as @Anon Ymous said. It will lighten your highlights. You may need to then adjust dev time a bit, too. The slide should not be so dark that you can’t just hold it up and look at it.
Well, I don’t have any hypo powder at the moment, so I’m just using straight dev. This was 12 minutes in HC-110 A, and I think it could use a bit of extra dev time. Gonna shoot a roll at 100 ISO and dev for 14-16 mins in HC-110 A tomorrow.
Hello! I'm working on replacing ammonia as the second bath for this reversal method using a copper rehal solution.
The exposure was not good, I shot a test roll for another purpose, but it shows that the idea works.
Instead of an ammonia-selective fixer, I use a concentrated calcium chloride fixer, a new version of a salt fixer. It uses 750g of calcium chloride in one liter of water and works in 15min at 35ºC.
The exposure was not good, I shot a test roll for another purpose, but it shows that the idea works.
Instead of an ammonia-selective fixer, I use a concentrated calcium chloride fixer, a new version of a salt fixer. It uses 750g of calcium chloride in one liter of water and works in 15min at 35ºC.
Very interesting, thanks!
Interesting. Does this work very well on non-reversal frames? If you haven't already perfected it there, I'd try that first since there are so many variables to consider in reversal processing.
Bumping this thread as I have a question.
In troubleshooting my process, I have discovered something rather odd. My copper sulphate bath rehaligenates the film just fine, if I go from the copper sulphate to a black and white fixer, the film clears right away. But, when I put the film in ammonia, it doesn’t do anything at all! It doesn’t clear or anything. I even tried putting it in the 5% ammonia that comes out of the bottle, no dice. What the heck could I possibly be doing wrong?
In troubleshooting my process, I have discovered something rather odd. My copper sulphate bath rehaligenates the film just fine, if I go from the copper sulphate to a black and white fixer, the film clears right away. But, when I put the film in ammonia, it doesn’t do anything at all! It doesn’t clear or anything. I even tried putting it in the 5% ammonia that comes out of the bottle, no dice. What the heck could I possibly be doing wrong?
In my experience, 5% ammonia is slow, like an hour or more. I used 7-8% and still needed 40 minutes at 38ºC. I moved to calcium chloride, which is still slow but does not smell. And ammonia will not clear all, it will leave AgBr I think that is what you are seeing.
To be clear, what I am doing is developing the film fully in the first developer after it has been exposed to room light. Then,I am bleaching in copper sulphate, and attempting to remove any rehalogenated salts with ammonia, but it is not clearing. I know they are being rehalogenated as when I put the same film into fixer it clears almost immediately.
Reduces, right?
Yes, but would it do that if there were bromide ions present from carryover? (But chloride ions are more electronegative, so I'm not sure it would make a difference if there also was some bromide.)
I hope someone who is using the bleach has an idea of what's going on. Good luck.
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- General Treegan
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- Reason: I misstake the threat
So you are rehaling a black film, right? Ammonia is slow when half of the silver is removed if an image is present. If you are trying to remove all the silver with ammonia you will need to increase time, concentration, or temperature.
Sounds like you haven't actually bleached it. Ammonia will only dissolve silver chloride (that's the principle of this bleach) and you must still have mostly bromides and iodides. That would happen if the bleach didn't bleach. Check acidity, time, and amount of sodium chloride.
What film are you using? Is it a film normally used in camera or is it a "process" film, a film used for making internegatives or projection prints? I ask as my attempt using this method failed when I tried to use ECP-2 projection film as a black and white reversal film. It seems that this film was a AgCl based emulsion so was completely incompatible with this selective fixing process.
Proposal: Two Rounds of Bleach
I have been experimenting with this and similar bleaches, and posting results in another thread. I would like to report an interesting finding, and propose that after the bleach step is complete, but before exposing it to room light, you do yet another pass through the developer + bleach.
Original Method:
Proposed Variant:
While experimenting, I noticed that the film darkened significantly during the 2nd development step. I speculated that one of the first two steps had "saturated" and only reached X% of the developed silver. But with that silver removed in the Ammonia step, we could do another round and remove X% of whatever was left.
Result: After a second pass through the bleach, for 3 out of 4 films that I tried (Rollei 80S, Kentmere 200, Wolfen NP 100), I was essentially able to get to the film base. For the 4th film (HP5+) the second pass makes the film more transparent but still pretty awful.
I couldn't get enough cut-outs of Rollei 80S, so I have to show you the results in two photos:
Photo #1: After only 1 pass through the bleach. The middle film strip went straight to the fixer, so it shows what the film base looks like. I do not know why the Rollei 80S one has a colored band. I can tell you that the part that became clear was inside the film canister and the part with the color was the bit sticking out.
In any case, after 1 pass, there's a significant amount of fog.
Just ignore the "ferric chloride" samples.
Photo #2: Second pass through the bleach. Here I also show the results for the last two films. With the notable exception of HP5+, the second pass through the copper sulfate bleach seems to get you all the way down to base fog, or thereabouts.
Q: Is the middle development step necessary?
I do not know. I hope it isn't because that would be another process that has to be timed since it'd be developing the original negative still. I did it because I wanted to gauge how much silver was left around after the first pass through the bleach. But that's just testing.
Q: Perhaps you just needed to develop it longer the first time?
No. I am sure that's not it. The first development step was 10 minutes in paper developer. That has to be enough to fully develop the film.
I would love to hear your thoughts.
I have been experimenting with this and similar bleaches, and posting results in another thread. I would like to report an interesting finding, and propose that after the bleach step is complete, but before exposing it to room light, you do yet another pass through the developer + bleach.
Original Method:
Dev 1 ↦ Stop
↦ Bleach (5 min) ↦ Clear ↦ Ammonia (2 min) ↦ Wash (2 min)
[ this is when you'd expose the film to room light ]
↦ Dev 2 ↦ Stop ↦ Fix
Proposed Variant:
Dev 1 ↦ Stop
↦ Bleach (5 min) ↦ Clear (2 min) ↦ Ammonia (2 min) ↦ Wash (2 min)
↦ Dev 2 ↦ Stop
↦ Bleach (5 min) ↦ Clear (2 min) ↦ Ammonia (2 min) ↦ Wash (2 min)
[ this is when you'd expose the film to room light ]
↦ Dev 3 ↦ Stop ↦ Fix
While experimenting, I noticed that the film darkened significantly during the 2nd development step. I speculated that one of the first two steps had "saturated" and only reached X% of the developed silver. But with that silver removed in the Ammonia step, we could do another round and remove X% of whatever was left.
Result: After a second pass through the bleach, for 3 out of 4 films that I tried (Rollei 80S, Kentmere 200, Wolfen NP 100), I was essentially able to get to the film base. For the 4th film (HP5+) the second pass makes the film more transparent but still pretty awful.
I couldn't get enough cut-outs of Rollei 80S, so I have to show you the results in two photos:
Photo #1: After only 1 pass through the bleach. The middle film strip went straight to the fixer, so it shows what the film base looks like. I do not know why the Rollei 80S one has a colored band. I can tell you that the part that became clear was inside the film canister and the part with the color was the bit sticking out.
In any case, after 1 pass, there's a significant amount of fog.Just ignore the "ferric chloride" samples.
Photo #2: Second pass through the bleach. Here I also show the results for the last two films. With the notable exception of HP5+, the second pass through the copper sulfate bleach seems to get you all the way down to base fog, or thereabouts.
Q: Is the middle development step necessary?
I do not know. I hope it isn't because that would be another process that has to be timed since it'd be developing the original negative still. I did it because I wanted to gauge how much silver was left around after the first pass through the bleach. But that's just testing.
Q: Perhaps you just needed to develop it longer the first time?
No. I am sure that's not it. The first development step was 10 minutes in paper developer. That has to be enough to fully develop the film.
I would love to hear your thoughts.
OP's idea has worked well on a dozen or so films that I've tested and IMHO doesn't require any innovation to make it work. Most of the difficulties people face are due to divergence from the process that they themselves introduce either inadvertently or because of ignorance.
Though it is called Copper Sulphate bleach, it requires two essential ingredients other than Copper Sulphate and water. First of these is Sodium Chloride which provides a source of Cl- ions without which rehalogenation of silver can't take place. If you omit Sodium Chloride from the bleach, you're not going to get a useful bleach for reversal purposes. The other essential ingredient is a strong acid like Sulphuric Acid or its substitute, Sodium Bisulphate. Without the strong acid, rehalogenation takes place at a very slow speed and can be incomplete. If you omit the strong acid or substitute it with a weak acid, your bleach might not be efficient.
Here is a formulation that has worked well for me:
Water: 700 ml
Copper Sulphate: 50 g
Sodium Chloride: 50 g
Sodium Bisulphate: 50 g
Water to make: 1 l
If one has access to Copper Chloride, then it can be used in place of Copper Sulphate and Sodium Chloride
Water: 700 ml
Copper Chloride: 50 g
Sodium Bisulphate: 50 g
Water to make: 1 l
Another source of problems is the use of low strength and aged Ammonia that might have lost most of its potency during its life. Fresh Ammonia works better and 25% Ammonia diluted to 2-5% at the time of use works even better. Use the diluted Ammonia one shot.
@koraks and other @moderators: it might not be a bad idea to lock this rather old and long thread.
Though it is called Copper Sulphate bleach, it requires two essential ingredients other than Copper Sulphate and water. First of these is Sodium Chloride which provides a source of Cl- ions without which rehalogenation of silver can't take place. If you omit Sodium Chloride from the bleach, you're not going to get a useful bleach for reversal purposes. The other essential ingredient is a strong acid like Sulphuric Acid or its substitute, Sodium Bisulphate. Without the strong acid, rehalogenation takes place at a very slow speed and can be incomplete. If you omit the strong acid or substitute it with a weak acid, your bleach might not be efficient.
Here is a formulation that has worked well for me:
Water: 700 ml
Copper Sulphate: 50 g
Sodium Chloride: 50 g
Sodium Bisulphate: 50 g
Water to make: 1 l
If one has access to Copper Chloride, then it can be used in place of Copper Sulphate and Sodium Chloride
Water: 700 ml
Copper Chloride: 50 g
Sodium Bisulphate: 50 g
Water to make: 1 l
Another source of problems is the use of low strength and aged Ammonia that might have lost most of its potency during its life. Fresh Ammonia works better and 25% Ammonia diluted to 2-5% at the time of use works even better. Use the diluted Ammonia one shot.
@koraks and other @moderators: it might not be a bad idea to lock this rather old and long thread.
One of the core rules of this forum is that all photography is valid. My understanding is that this rule extends to how we choose to process film. As you correctly noted, more than one person here has chosen to spend time and energy in an attempt to replace the original acid with something else. The reasons for doing so have been discussed in this thread and I shall not repeat them. Whether you personally share or empathize with the reasons given does not seem relevant. I fail to see how anyone benefits from hostility toward efforts to make other acids work. As far as I can tell, no harm comes to you because other people choose to pursue their hobby in a way that you consider wasteful.
I'll bring it up with the team, but looking at it from my perspective, I see no reason presently to lock it. Whether or not experimentation is sensible or useful is not a question we use as a guideline in forum policy. As long as posters adhere to forum rules, we don't intervene.
We do of course from time to time split off posts into a new thread, but I also see no very compelling reason in this case to do so.
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