John wrote: > I use the formula, y=.91x^1.51, where x is the metered time and y is the > corrected time. It approximates the reciprocity pretty closely, and has > worked for me for exposures up to 2 hours on FP4+, which shares the same > reciprocity failure as HP5+. I've always processed normally, with pmk pyro.
This is interesting, a variation on the formula I was given. Where did you get this formula? I wonder if such formulas exist for all films? Maybe if I used another factor, like your .91 above, with the Kodak chart, I could work out a similar formula. I was only looking for an exponent the first time I tried. --shannon
