paper reversal process + bromoil

[noofzz]

Hello!

I shoot paper and develop reversally. Now i decided to make it "more fun" and after second development i bleach it ( the positive) in bromoil bleach and then apply paint.

Reversal proces:

Develop
Stop
Bleach (bichromate+sulphuric acid)
Neutralize (sulphite)
Exposure and second dev

Bromoil part is:

Bleach (copper sulphate+bromide+bichromate)
Painting

But i have some problems/misunderstanding:
The paper is all blue-green after bromoil bleach, it was the same even after all-night wash in water. Today i tried to put the greenish print to stop bath, it eliminated the colour, but when i occasionnaly exposed the print to direct sun it became brounish... I don't know what is it, i couldn't try fixer or something else, because it was in the street

.
Actually i don't understand how does the bleach work. Why does the first bleach not tan the emulsion? Or the sulphite bath untans it after bleach? What happens to silver in the both bleachers, does it leave the paper or stays in some different invisible form? (I know that after bichromate+sulphuric acid bleach there in no silver, were it was metallic, but all the undeveloped halogenides stay untouched)

 

[noofzz]

Well, i used fix, and the brown colour has gone.
But i still don't understand how does the bleachers work. Why does one remove silver and the other doesn't?

 

[mrred]

To quote a post from PE "the reversal B&W bleach relies on forming Silver Sulfate from the NEGATIVE Silver image. This dissolves in the bleach leaving POSITIVE Silver halide". ((there was a url link here which no longer exists) post #5)

My impression (guess) is the second bleach is dropping the copper in place of the silver, hence the blue.

I would expect a fix is needed at the end of the reversal to remove the remaining undeveloped silver from that step. Combined with a *really* good wash might eliminate your "blue" fog.

All said, I have never done bromoil. I may be way out.

 

[mrred]

I looked up the bromoil process (http://www.alternativephotography.com/wp/processes/bromoils/making-a-bromoil-print), and your reversal print definitely needs to be fixed before you start. If you have not been fixing your reversals before, you will have issues over time.

There is a mention of not using hardening fixers.

 

[Ian Grant]

Well, i used fix, and the brown colour has gone.
But i still don't understand how does the bleachers work. Why does one remove silver and the other doesn't?

Re-halogenating bleaches convert the silver to silver Halide, (Iodide, Bromide, Chloride) and the Silver Halides are insoluble in water. The bleaches used for Reversal processing form soluble Silver Sulphate which is washed out of the film in the bleach and rinse stages.

Re-fixing shouldn't be needed after reversal processing as the 2nd developer is to completion.

The Bromoil bleach is re-halogenating but dichromate hardens the emulsion as it bleaches which is the tanning effect.

Ian

 

[noofzz]

Well, so the dichromate oxidises silver, and sulphuric acid forms soluble silver sulphate? And the bromoil bleach: dichromate oxidises silver, and potassium bromide forms silver bromide?
What is copper sulphate for?
Can i replace KBr with table salt, NaCl to form silver chloride in emulsion?

And I tried painting a print after reversal bleach, but it didn't work. I did see a pale orange "bleached" image, but it disappeased after washing or sulphite clearing bath, and painting didn't form image....
So i don't understand why dichromate works (tans) good in one bleach, and doesn't in the other....

 

[Ian Grant]

You can most likely us Sodium Chloride, I do with some toners it gives a warmer image than Bromide.

The Copper sulphate acts as a mordant for the Bromoil inks, it's also used in the Etch Bleach process.

Ian

 

[Raghu Kuvempunagar]

Hello @noofzz,

I know this is an old thread, but I wonder if you made progress subsequently in combining bromoil with reversal. Are there any examples you can share?