Hi, I guess I've been AWOL from this thread, but in my defense I don't have anything directly useful to add. Although I've worked in photography my entire adult life, I've never had occasion nor need to study acutance. Not that it wouldn't have been fun, just no way to justify it from a business standpoint.

Regarding information from Michael Kriss, he authored the chapter on image structure in Theory of the Photographic Process, 4th edition (James). If you can find a copy, there are about 40 pages of dense reading. I don't see it as directly practical info, mostly it applies fairly advanced mathematical treatments to things such as spread funtions. If you're familiar with the convolution theorem and Fourier analysis, then you might breeze right through this, but it's mostly beyond me.