Quote Originally Posted by DREW WILEY View Post
Different combinations of film and developer have different curve configurations. ... And I'm more concerned about the shape of the toe than the overall range per se.
I just drew a set of curves for an APUG'r and the lowest contrast negs have beautiful smooth toes that I know I could just reach right into to print a negative shot at half box speed. If I took the 0.1 density to base EI, it would say quarter box speed. But half box speed is more appropriate.

This is one of the factors I believe leads to lower Zone System speed ratings. When you develop N-1 etc, you may not achieve full speed. Especially if you rely on 0.1 density as the point where you take your speed reference.

And when I know that more of the toe is usable, I am reluctant to use 0.1 density-based speed.