Charlie, I have to admit that my normal development time used to be 10 minutes. I used 8 minutes because that was what our test procedure recommended. I will repeat the test tonight and go back to my 10 minute regime.(posted 8500 days ago)My normal rating of 200 is for daylight. However, I also exposed a few frames of normal scenes (contrast range of 5 stops) using the blue photofloods and those printed easily at my usual standard printing time.
The density readings are net density. The fb+f density has been subtracted.
The test procedure is meant to find the E.I. that yields a Zone I negative with a 0.1 density. This means if frame 1 is Zone I (-2 stops under) then my E.I. is 100. If it's frame 3 (-3 stops under) then my E.I. is 200. If it's frame 5 (-4 stops under) then my E.I. is 400.
My thanks to you and Ed (and to others, in anticipation) for taking the time to think about this. I'll try to return the favor by putting up my results with explanations when (and if) I get to the bottom of this.