My comments were meant for no one here on this thread at all. Sorry for the misunderstanding. I apologize for any confusion.

As for testing Bill, I suggest using a WR 98, 99 and 70 (or equivalent narrow cutting filter set) over a step chart and exposing. An in-camera exposure is difficult to read, but a 3 color filter set with and without dye will give you the exact speed change in each region affected in terms of Log E (stops) speed change.

I've tried the method you describe, Bill, and it is just not clear cut enough. However, if you wish to send me a sample, I'll expose it with my spectrosensitometer.

PE