Quote Originally Posted by andrew.roos View Post
I agree that Howard Bond's data is a good resource. I recently measured reciprocity failure for Delta 100 (see post here) and my measurements differed substantially from the chart in the Ilford data sheet.

One of these days I should sort it all out, I suppose. I used Delta 100 in one of my early Pinhole Day forays and used a chart put out by Pinhole Designer that included compensation for reciprocity failure. The results suggested to me that the exposures had been excessively compensated, so maybe the P.D. software designer used the Ilford data. (More recently I've used Acros and ignored the whole thing.) Probably within the exposure range most "ordinary" people use, there's not enough of a problem to justify grinding through the tests.