Quote Originally Posted by Michael R 1974 View Post
Shifting the curves is indeed helpful because you normalize for speed. For example I know if I rate Delta 100 at EI 64 and TMX at EI 80 and develop them both in XTOL 1+1, the curve shape is nearly identical up to the areas above zone X-XI where Delta has slightly higher highlight contrast than TMX.
Mike, here are the curves I'm getting for TMX and Delta 100:

Del100-TMX.jpg

It's true that the Contrast Index (done Kodak's way) of TMX is 0.04 higher, but I doubt that would account for this difference in curve-shapes. Also, Zonies would say these have about the same CI because they measure from Zone I to Zone IX, which goes out to X=0.3 where the curves converge. BTW, this graph is why I mentioned that Delta 100 has a longer toe. Can you post the curves you got for these? What CI are you getting? I'm wondering if your graphs are closer to my TMX or Delta 100 graphs. I'm also wondering if I seriously overdeveloped my TMX.

Mark Overton