I have done that experiment, but the color meter readings I got through the high grade Ilford Filters (4 and above) were not accurate. I suspect that is due to a sharp cutoff in the spectrum on those filters. As you have probably noticed, the Ilford #5 filter is not the same color as the magenta filter in a dichroic head, though they should give the same contrast grade. Problem is your PM2 probably won't read those high-contrast 'non-magenta' filters correctly. Try it and see.
Originally Posted by HTF III