Rehal & redevelop for "chromes" developed in B&W ?

pdeeh · Feb 10, 2016

I recently developed a couple of sheets of film in D23 , and fixed as normal, having been given to believe that the film in the holder was FP4. (I also just ascertained that I have yet another holder loaded with Velvia, which is of almost no use to me )

As it turns out, it was Velvia 100F and thus I have a couple of very murky monochromes which are of not much use to me, though I might hang on to one as it is and see if I can make some sort of contact print off it.

As the film hasn't been silver bleached, I can't see any obstacle to dunking it in a rehal bleach and then - for a bit of fun - doing a cross-process in C41 (which is what I have to hand) ... just checking in to see that I'm not missing anything stupidly obvious?

Anon Ymous · Feb 10, 2016

This assumes that the couplers that were originally present in the film and formed the dye image during development are still there. Without them, I don't see how you'd get any colour.

pdeeh · Feb 10, 2016

It does indeed assume that, but as one can develop a C41 negative in black and white developer, but nevertheless rehal and redevelop in C41 chemicals to produce a colour image, I am hoping that - by analogy- E6 will be the same.

Certainly with C41 films, the dye couplers etc are only activated by the oxidation products of the colour developing agent as it develops the silver image, and thus when developed in a regular b&w developer like D23 they are left extant through the processing - hence being able to later redevelop as colour.

However, my understanding of E6 is even more limited than my understanding of C41, hence my checking in to see if it will work analogously.

Rudeofus · Feb 10, 2016

The film hasn't been bleached, but I would assume it was fixed, therefore there is no silver halide left in exactly those areas which should see color development in E6 reversal processing.

The best you can hope for is some sort of cross processing, i.e. you bleach the silver you have, then go E6 CD, (bleach, fix) or BLIX, final rinse, with wash in between each step. This won't give you slides, or only very strange looking ones, but it will give you something which you could resurrect in a hybrid work flow.

pdeeh · Feb 10, 2016

Yes I realise that it won't produce a reversal Rudeofus, as I said in my OP I'd try a C41 cross process.

I simply wanted to check that E6 worked similarly to C41 inasmuch as b&w processing would leave the couplers etc in place.

Which I think you have confirmed.

Athiril · Feb 10, 2016

Yes the couplers are still present and will work, have done this several times.

Ferricyanide + Bromide bleach, clear and wash, then C-41 or start from E-6 colour dev step.

Rudeofus · Feb 10, 2016

I had the impression you wanted to cross process since "which is what I have to hand". What my posting pointed out, that regardless of which chemistry you throw at the problem, some form of color negative is all you'll ever get from this strip. If you use RA-4 or E-6 color developer instead of C-41, you'd even use the correct color developing agent, which according to some here could lead to better archival stability.

pdeeh · Feb 10, 2016

Rudeofus:
I think you assumed that I wasn't sure what I would be getting, which wasn't (and isn't) the case.

However I hadn't explicitly said that I expected a cross-processed negative as a result, so I suppose your clarification is helpful should someone else find this thread when looking to answer a similar question.

Note also that you didn't have to assume I had fixed the film, as I had explicitly said I had done so in my OP.

Athiril:

thanks.

Kirks518 · Feb 16, 2016

You can redevelop (or "accelerate") color film that was developed in B&W chemicals. You can see samples, and an incomplete explanation Dead Link Removed and Dead Link Removed.

You will need potassium ferricyanide, and another chemical whose name escapes me (I'm on my work computer). Both are available at freestyle photo. I personally have not done it, but I do have the potassium ferricyanide, and plan on trying it one day for fun. If search long enough on the web, you will find the instructions on how to do it.

pdeeh · Feb 16, 2016

Hi Kirk -- if you have a look through your old PMs you should find one or two from me about that very subject

Rehal & redevelop for "chromes" developed in B&W ?

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