Be prepared for surprises. Copper sulfate bleach relies on bromide/iodide emulsions, and some papers have Silver Chloride, which will wash away with the ammonia clearing bath. Some papers will work, others won't.
Be prepared for surprises. Copper sulfate bleach relies on bromide/iodide emulsions, and some papers have Silver Chloride, which will wash away with the ammonia clearing bath. Some papers will work, others won't.I'm glad this thread bumped up to the top again, because I remember reading it but had forgotten the details and couldn't find it again.
I want to try this idea with paper, and I have everything I need already here, so it's just a matter of finding time! ( so sometime in the next few years)
I really like this! Any suggestions whether this AgCl fixer could be made from Ammonium Chloride instead of smelly Ammonia?
Remember that any bleach containing Ammonium ion or Chloride ion is also, to some extent, a blix. This will cause loss of AgX in the remaining positive image in reversal B&W.
PE
Sorry for late reply. The main difference between Ammonia and Ammonium Chloride is the presence of Chloride ion, which works as restrainer in low concentrations and as silver solvent at high concentrations. Therefore Ammonium Chloride would have to be used in rather high concentrations (read 30 - 100 g/l). I have not personally tried this yet, but may end up trying it at some point with photographic paper. I shall report here when I have something practical.@Rudeofus: do you now have a solution for this question and can you kindly share it?
Sorry for late reply. The main difference between Ammonia and Ammonium Chloride is the presence of Chloride ion, which works as restrainer in low concentrations and as silver solvent at high concentrations. Therefore Ammonium Chloride would have to be used in rather high concentrations (read 30 - 100 g/l). I have not personally tried this yet, but may end up trying it at some point with photographic paper. I shall report here when I have something practical.
Now that this thread is three years old:
Is the copper sulfate bleach in Athiril's formula able to be the standard b&w film reversal process?
Any shortcomings in practice compared to reversal processes based on Permanganate ort Dichromate bleach?
I am very impressed with this work ,,I am one of those who use Copper Sulphate + Sodium Chloride bleach for B&W film reversal. My experience is limited to Orwo UN54 roll film and Shanghai GP3 sheet film. I've no experience with Permanganate/Dichromate bleaches. Apart from the slowness of the bleach, I don't have much to complain about Copper Sulphate bleach.
I am very impressed with this work ,,
Greetings to you .
Copper bleach is really very great.Thanks Mohmad, you're a generous man.
Since my last post in this thread I've used Copper Sulphate bleach on several other films including Adox CMS 20 ii, Ektascan xray film, Astrum Foto 10, Astrum Foto 200, Kodak Tri-X, Kodak TMax 400 and Kentmere 400. There's not much to complain about the bleach in my experience except its slowness though YMMV.
For paper reversal I use dichromate bleach.
However, if you want to significantly speed up the process, you should add 5 ml of sulfuric acid (37%).
For paper reversal You can use the same solution, but with a 1: 4 dilution, you will not need (dichromate bleach). You will get very cool toning.
Hi brother.Yes, sulphuric acid does help. I use Sodium Hydrogen Sulphate as it is safer to handle.
I used the Copper Sulphate bleach formula given here:
http://real-photographs.co.uk/formulae/toners/copper-sulfate-bleach/. It's reproduced from Tim Rudman’s ‘The Master Photographer’s Lith Printing Course‘.
For paper reversal, I didn't dilute it and maybe full strength bleach is too strong for paper. I should try the recommended dilution (1+9) and see if it works. Thanks for the suggestion.
I'm still worried about the ammonia rinse that follows Copper Sulphate bleaching. It could be another reason why this bleach is not best suited for paper reversal. Fomaspeed, the paper I use for reversal, is a cholorobromide paper. Which paper did you use?
I apologize ,,Hi brother.
- We may need to get the opinion of the Austrian engineer / Rudi to confirm or deny what I told you. He has much deeper experiences
You live in India ,, and it is the main source of most chemical raw materials .. Why worry?
Everything is available to you.
Trust me, you are going great and very successful ,,
Getting anhydrous copper sulfate is easy in India, and you will get it for a cheap price, and you will get better results and higher quality (in my view).
Using deionized water will help the process to be clean and clean.
Sodium iodide also has no iodine, which should help in the purity, cleanliness, and accuracy of the process.
Sulfuric acid (37%) is very cool and will add speed to the process.
The recipe you use is acceptable.
But I use much higher concentrations in order to speed up the process, you can increase the concentrations 100% (except only 50% sulfuric acid) Yes life is experiments.
- There's no problem ,,
Dilute the solution of ammonia (it is a necessary evil). Not everything in this world will be easy and beautiful. Inevitably, there are some obstacles and troubles in life. And you have to bear and adapt to the issue.
- The use of copper bleach in printing does not necessarily require the use of ammonia solution after bleaching as is the case with negativity. The matter in printing is very different.
- I wish you all the best, my dear. God bless you ....
The ammonia solution is important for the success of the copper bleach.
I filtered this liquid 4 times with a cotton swab.This correlates well with my experience with this bleach. For saving costs, it's possible to reuse ammonia a few times, but the liquid becomes muddy with use. Best to discard when you see first signs of muddiness.
Copper (Cupric) Sulfate..................................50 g
Citric Acid (99.9%)..............10g
Sodium Chloride (Common Salt)........................... 50 g
Water to make..........................................1000 ml
pH is quite low, at just under 2. It may not need this much citric acid.
As per @Athiril , 2 mins in 2.5% ammonia leaves a clear, unstained strip of film. I will do some more testing with real images later this weekend.
Today I did some testing with Tim Rduman's copper sulfate bleach (http://real-photographs.co.uk/formulae/toners/copper-sulfate-bleach/) but I decided to try Citric acid instead of the sulfuric acid. I have citric acid, and it's a lot safer to work with than sulfuric acid. The following bleach seems to bleach down a blackened film leader in 3 mins at 19C:
Copper (Cupric) Sulfate..................................50 g
Citric Acid (99.9%)..............10g
Sodium Chloride (Common Salt)........................... 50 g
Water to make..........................................1000 ml
pH is quite low, at just under 2. It may not need this much citric acid.
As per @Athiril , 2 mins in 2.5% ammonia leaves a clear, unstained strip of film. I will do some more testing with real images later this weekend
@Raghu Kuvempunagar how long does the copper sulfate bleach normally take for you? I know you have used it a lot.
Nice! I can get copper sulfate pure enough for our purposes at the Big Box home improvement stores (sold for clearing roots out of drains). I actually have sulfuric acid on hand (30% strength, for battery filling), but I think I have some citric acid, too, and I'd worry less about handling that. ORWO DN21 has a very clear base, I may have to give a try to reversing a test roll.
Any evidence on how long this bleach keeps after mixing? One tank, one day, a week, a month, or as long as it stays blue?
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