Very useful article, Ed. It quantifies the things that can be quantified, but acknowledges the fact that whatever the density range, Pt/Pd will still have a different look from Azo, because of the surface reflectivity, among other things.

Gordon Hutchings has come around and recently said that ABC is probably better for contact printing on Azo than PMK, because ABC produces a longer scale negative, and the grain masking effect of PMK is not so important for contact prints.