Quote Originally Posted by Photo Engineer View Post

The paper sees the base + fog, and so lets exaggerate this situation to 2 films with a Dmin of 0.2 and 1.0 respectively. Since they are vastly different, you would not print the foggy one at all. Subtracting PE
I'd agree in a case like this because something is clearly wrong with a Dmin of 1.0. But if we have normal levels of fog for both films (each being different back to my Delta/TMX example), what difference does a longer printing time (within reason of course) make? If the Dmin levels are normal, so that we have no issues with image structure characteristics in the negatives etc, if two films have identical plots for net density (gross minus Dmin), as long as the printing exposure is increased for the film with higher Dmin, the macro gradation in the resulting prints should be identical. Sorry if I'm being repetitive but I'm still not quite following. I suppose one might ask "how do we know what Dmin is normal for a given film/processing combination?". But plotting gross density doesn't answer that question.

Mark - apologies for sidetracking the thread. I am just as curious about your question!