[mr.datsun]

Mrred, I don't get it : you develop and fix a strip of unexposed film. Then why develop it when there will be nothing to develop if it's unexposed, and you'll end up with a blank strip ? How do you recognize the correct first development time from this ?

Tofek. My take on it is, that with Mr. Red's method, you do a series of developer time tests. Say 4, 6, 8, 10, 12... (or smaller increments) until you get fogging on the base. Then with the last one that shows no fog or just a touch of fog – that's the max amount of silver you can ever get out of the film with your developer before you've begun to lose the shadow detail and contrast. Because even with blank film the developer will eventually start working on unexposed/unexploded halides – to preserve the clear base you have to stop development at that point.

I've been thinking about this and decided that i could take 6 or so small strips of tri-x and then put each one in turn into the dev, time it , stop it, fix it and then compare them at the end. I thought I could try and mark the strips with numbered notches. Use one mix of dev for the whole test and it's done - ideal development time is sorted for good. (Then perhaps do it for a other dilutions for completeness or if the contrast needs adjusting in the final exposed image tests.)

It separates out the question of ideal development time from the one of exposure.