slide film processed in b/w chemistry ?

I recently accidentally processed a roll of Kodak Portra 160NC in divided Pyrocat HD. Silly me for not looking closely at the label. The results scanned beautifully and hold great detail in shadows and highlights. That's all I'll say about it on this fully analog site. I'd post my image, but it doesn't belong here. All said, I'll not be repeating this process intentionally in the future.

Peter Gomena

As someone has pointed out to me, this is not a simple problem.

Some films use a CLS (Yellow Silver) filter layer and others use yellow dye layers. Both are intended to be removed by the color process in one way or another. B&W processes may or may not remove the dyes, and generally never remove a CLS layer.

So, I cannot give a simple answer on the yellow color. It will depend on your process and your film. Sometimes you will get the yellow color and sometimes you will not. I cannot predict this event in advance, and so when I say you will get a yellow negative, I was choosing worst case!

Sorry for any confusion it may have caused.

PE

Correction to last post of improved E6 slide developed in D76

Hi guys,

I now realized I actually made a big mistake in describing what I did to improve the E6 negative, it was some time ago and I'd forgotten the details.

Instead of doing a single bleach / redevelop in a ferricyanide / thiourea toner, I did a bleach / redevelop in ferricyanide / B&W Ilford multigrade paper developer, and that in a couple of cycles (two or three).

Successive cycles of bleach and redevelop removed much of the dark brown cast, and made the negative printable, although the negative keeps looking a nice sepia brown, but the latter tone has nothing to do with thiourea sepia toning. Of course, if desired, the negative could be toned with a thiourea or selenium toner as a final treatment to either improve permanence or contrast, it is still regular silver in the image after the successive bleach / redevelop cycles in ferri/multigrade paper developer.

Here are the texts in another thread I started describing it, and also the before and after images of the negative. Note the vast improvement in printability due to removing much of the cast.

TEXT FROM OTHER THREAD:
"OK, since I don't have chlorine bleach, I have attempted to use a ferricyanide bleach as used with my sepia toner. Interestingly, the image did lighten up over all and became more transparent, however, still far from colorless (more like a yellow filter).

I than redeveloped it in plain B&W paper developer. The sheet very much turned back to it's original form, however still lighter (so probably quite a bit easier to print). Some of the cast thus was lost.

Overall, the effect of bleaching and redeveloping thus confirm that at least part of the cast is indeed colloidal silver. I don't know about the remaining color, it might be a dye that is not released in any of the common chemicals."

AND:
"As I wrote before, I have cut up one of the chromes for some experimentation. I have know bleached and redeveloped (in paper developer) the chrome twice. See the attached image.

The upper part is the unmodified transparency as it came out of the D76. The lower part is the bleached and redeveloped transparency. Notice it has considerable more transparency and contrast.

It might be worthwhile to do the same to the other transparency and see if I can print something. I don't expect any great results, but it is fun to try out."



Sorry for any possible confusion. The full thread I started back then is here:

(there was a url link here which no longer exists)

Marco