Donald - I knew I should have gone into more details when I made that post...
First let me say that my comments were based on my experience with PMK, and almost exclusively with PMK. I have used ABC-Pyro, but that was nearly 25 years ago... So my comments in that post and this one here are intended towards using PMK (The concepts I've covered the last 10 pages of this thread could be applied to any staining developer.) And I would only apply my comment about the appearantly lower grain to my experience with PMK. I do understand that ABC-Pyro has a reputation for more grain.
Donald wrote, "My results are exactly opposite of your suppositions in this regard."
Which of my suppositions?
Donald wrote, "The proportional stain exhibited by certain staining developers is counter productive to highlight tonal separation on VC materials. Most notable in this regard is the stain color of the PMK pyro formulation. "
Donald, I agree that there is not better "highlight separation" when using PMK with VC papers. Not only is not better highlight separations, there is highlight compression. I did not say anything to the contrary about that above.
What I said was "For graded papers, I find that stained negs print just like non-stained negs. I probably would not bother using a staining developer unless I was using VC papers."
I would use PMK to NOT get better highlight separation - I would use it to compress highlights - by using VC papers. I was trying to respond to Patrick saying, "Now I am pretty well set for deciding which grade of paper to use. [By using his densitometer.] Heaven help me when I go to VC!" Again, I probably would not bother using PMK with graded papers, although it would give you the option of using a VC paper and then being able to compress the highlights. Kind of a dual-purpose option, again like the PyroCat with alt processes.
Donald wrote, "In fact the proportional stain is most effective with graded materials, I can not understand your statement about stained negatives printing the same as non stained negatives on graded materials. "
I guess I need a clarification of what you mean by "most effective". Perhaps we have different goals in mind with our choice of developers. And see the response to the next paragraph -
Donald wrote, "Have you done any testing of the reflection density in the zone VI and higher tonal regions on prints made from negatives developed in both types of developers?"
Yes, I certainly have. I found that once you get past the issue of trying to match development times, the shape of a PMK neg printed on a graded paper looks very much like the shape of a non-stained neg printed on a graded paper. The curve has a nice, straight-lined portion in the middle. As far as the graded paper is concerned, the stain looks just like silver. The graded paper can't tell the difference.
When printing a PMK neg on VC paper, the highlights are compressed and then print darker than a similar exposure would have if a non-staining developer was used (or if the same PMK neg was printed on graded paper). Instead of a straight-lined portion to the curve, you have a curve that is essentially all toe until you get into the darker zone numbers. The toe of the curve on the print is very long.
I'm not the only one that has found this - it is exactly what Howard Bond found in his second, much better researched article on PMK that was just published in the Sept./Octo. 2004 PhotoTechniques magazine. See his Figure 5. I get the exact same results.
Are you finding results different from this?