Ilford Reversal processing

Hi, Folk:

I'm now trying to process b/w positive by following "Ilford Reversal Processing" manual.

I'm thinking to process it by Jobo CPP-2. I'm wondering how to re-calculate all the processing time?

As my understanding, all the timing is not that critical except 1st dev, but how can I judge the dev time without densitometer? Any suggest timing?

Thank you very much for your time and help.

Sincerely Tsai, Ching-Yu

If you plan on using a potassium permanganate bleach, timing and temp and concentration will be critical, as it damages the film. For B&W reversal, I prefer a dichromate based bleach, as it's reliable.

I guess you will have to do your own test runs anyway to determine DEV time and effective speed for your specific gear and workflow. That being said, I am just in the process of changing over from inversion to rotation on a Jobo (not reversal, just plain negative process), and my so far limited experience with rotation indicates that at least with Xtol the DEV times have to be shortened only slightly (maybe 10%). But this will depend on the developer you use and maybe also the temperature chosen for rotation, the kind of inversion scheme you used before, the type of drum you use etc ... In a reversal process, small changes in exposure and dev can make a bigger difference, so it really boils down to doing your own testing... And I mean practical testing... Going out and shooting normal motifs, bracketing exposure and varying developing times. And honestly I don't think you need a densitometer for that as it is very easy to judge a positive by putting it on a light table or projecting it...

A word of caution. Several previous posts concerning Ilford's method indicate that people run into trouble when they deviate from Ilford's instructions. Reversal processing is more demanding than negative processing.