Black and white film--reversal processing question

S.Frank · Jan 22, 2014

I recently processed two rolls of Tmax 100 with a reversal kit from photographer's formulary, with less than optimal results. The film has an irregular splotchiness, sometimes looking like splatter. In some cases the top and bottom edges of the frames are darker in tone, like a stain. I did a continuous agitation with my bleaching step; I wonder if I need to do a better wash afterwards or perhaps a more rigorous agitation regime with the clearing bath solution.
Any thoughts?
Thanks

--Sean

johnielvis · Jan 22, 2014

could be anything. Maybe not enough rinse after the development--residual developer reacting with the bleach to make it less active. Could be stuff in the water you used to mix it causing problems. Could be not enough solution in the tank--did you fill it to cover the film with all solutions? You can pull it out after the bleach step and check if it's ok or not before the clearing bath and do the clearing bath by inspection--this will also serve to give you the light re-exposure. Something mixed wrong? maybe post a color pic of a strip of the film?

cliveh · Jan 22, 2014

How did you reverse the image?

S.Frank · Jan 23, 2014

reversal

Everything was done by the book--proper volumes of chemistry,temp accuracy. Re-exposure was done with a 150 watt bulb. I suspect the problem is either in the washing or clearing bath, so I will do these more thoroughly with my next two rolls and post the results.

Thanks for the input

Sean

jochen · Jan 24, 2014

Hello,
I suggest that the bleaching bath is of the permanganate/sulfuric acid type. I read somewhere that this chemistry is not as reliable as the former dichromate/sulfuric acid type which is toxic and carcinogenic. It seems to make more problems.

Gerald C Koch · Jan 25, 2014

The permanganate bleach can be less reliable since if the pH becomes alkaline manganese dioxide will precipitate. If this happens in a region of the film you will get a brown to black stain. The permanganate bleach can also cause softening of the emulsion. The dichromate bleach causes less problems and is safe if one is careful. Before disposing of the dichromate bleach add a bit of sodium sulfite to it. The color will change from orange to green showing that the chromium has been reduced to the less problematic Cr (III).

Gerald C Koch · Jan 25, 2014

Since light fogging is done to completion the presence of water droplets on the film during the process would have no effect.

A simple fogging developer is sodium sulfide which produces sepia images.

Gerald C Koch · Jan 27, 2014

Lemme disagree on this: a chemical fogging redeveloper is much more potent than light reversal

I think that the difference in density produced by the two methods would be very small if it existed at all. An interesting experiment for anyone with access to a densitometer.

Black and white film--reversal processing question

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