Quote Originally Posted by Kirk Keyes View Post
This is known as the Exposure Scale. It's the x-axis in your BTZS software.



This is the Density Scale -From Answers.com:
A value for the range density for a photographic material that corresponds to the difference between the maximum density and the minimum density. Also known as net density.

It's the y-axis on the BTZS software.

You're comparing apples and oranges when you ask that question.

The Azo and pt-pd paper have a low contrast, hence the greater exposure scale than greade 2 silver paper. Combine this with negatives that have a high density range, and you get a print of normal reproduction range.

The Azo print will produce the neg with greater d-max than the pt-pd, but the same range of exposure scale is recorded onto the paper. (By the way, my Ilford MG IV FB with grade 00 can print that same negative exposure scale range.) This is the point that I was trying to make in my earlier comment. However your MG IV FB will not be the same print as a Pt-pd or even an Azo print. It will not have the presence that Azo will show...and it will not have the delicacy of tone that a platinum print will have.

I'm sure PE can explain the multiplication of negative and paper gradients/contrasts to come up with a normal reproduction range and how it applies to this question better than I...
This still does not answer the position that PE made that higher dmax is necessary for a longer tonal scale. If a material such as Azo Grade two has an exposure scale of 1.65-1.70 and a grade two material such as Nuance has a exposure scale of 1.25 with a condenser enlarger than something is darned sure different. I agree that it takes a negative of corresponding density range (high density minus low density and not minus FB +fog) to match the paper. The paper or process (in the case of Pt-pd is longer scale) or lower contrast in your description.

By the way, PE, I do understand curve shapes so there is no need for you enlightenment on that score.