Hi Stephen,
well after your lengthy treatment of this I think I have come full circle. I'm sure I initially interpreted you correctly when I thought you were encouraging me to strongly consider contact printing the step wedge rather than doing the in-camera, low flare option I last described. Now I'm convinced you're saying it doesn't matter which method I use as long as I understand the theory sufficiently to properly interpret and apply the results.
I also thought you were indirectly challenging Ralph's method by asking "How is this possible": however in your last post you then finally managed to explain how it is possible without invalidating Ralph's method.

(You wrote:"Ralph likes to use a negative density range of 1.20 for normal. His normal CI (average gradient) is also 0.58. As both aim Contrast Indexes are identical, that means that any scene photographed and developed to a CI of 0.58 is going to be the same on the negative. How is this possible with different aim negative density ranges")

So with my new ultra low flare setup I intend on repeating my tests, hopefully this weekend.

Quote Originally Posted by Stephen Benskin View Post
First, I do need to make a small correction in your interpretation of the negative density range that matches 0.58 or the 0.57 that is used as the aim avgGradient in the WBM monograph. I’ve drawn a line through the average conditions to the point that is labeled “Typical Diffusion Enlarger“. As you can see it has 1.20 as the negative density range for an avgGradient of 0.57. So, we need to adjust your 1.30 down to 1.20..
I did make a typo, but not the one you corrected ! I actually meant to write
"in Ralph's nomograh the ISO std of 0.615 (not 0.58) matches a neg. dens. range of 1.29 (which I rounded up to 1.30)" you can see this is where the ISO Standard arrow is pointing on the far LHS of WBM's nomograph you attached.

Its way past my bedtime now !

rgds
Peter