Can anybody shed some light for me on the following question: If I measure a density range in a negative from say .90, can one determine the filtration for the paper from this? I seem to remember an article where it was stated that every 0.3 density increment amounts to one step in filter grades, but I can't find it any more. I use a Heiland Electronic TRD2 densitometer and an Opemus 6 with a Meograde variable contrast head for B&W printing. This head permits one to dial in filter grades from 5 to 0. Thanks for any suggestions.