The second way of evaluating image stain is the Pat Gainer recommendation of bleaching out the silver image - thus leaving any stain image behind.
BTW, I am a Pyrocat-MC user. Most of my development is with minimal or semi-stand agitation. BTW, I get excellent results with Sheet film. 35mm and 120 roll film as well.
Isn't it true that when one substitutes various chemicals in a formula, you are really formulating another developer? Is the pyrocat hd still pyrocat hd if you substitute ANY of the chems for another? Isn't that what happened when Sandy King introduced the various changes in the original Pyrocat HD?
And, if you bleach the developed film the stain (if it exists) will remain.
Preservation of both Deep shadow detail and Highlight detail is a particular attribute of the Pyrocat family of developers.
Let's try and correct the record.
Staining developers are an asset for both VC and graded papers. The yellow-yellow green - orange brown stain with PMK retards blue and green light. The stain with PMK is proportional to the silver density. VC papers are sensitive to both blue and green light and graded papers are sensitive to blue light. The color of the stain retards the transmission of blue and green light and thus is effective for both types of papers.
Shadows with PMK are not muddy if the proper exposure is given to the negative. You should always test for your personal EI - however you do the testing you should aim for a zone 1 density of .1 above fb+f.
I did a test a few years ago with PMK and Pyrocat. I tested for EI and dev time for a vc paper with no filter - approx the same as a #2 filter. I then shot side by side comparisons, processed the film and made direct scans of the negatives. The PMK negative had much better high value separation. I would have been happy to change developers if the Pyrocat gave me better tonal separation up and down the scale. I did not feel it did.
If you have not read The Book of Pyro by Gordon Hutchings I would strongly recommend doing so. It is the most definitive and comprehensive work on staining develpers and how they work. You can get a copy form Bostick and Sullivan or the Photographer's Formulary. Gordon will also be doing a workshop and a presentation on staining developers at foto3.
well thats a pity. I'm not asking which is best because there is no such thing. I am asking what is the difference on only graded papers between the two developers. I would be more than happy to know one is better for highlight separation and one is better for shadow separation because that would give me two different tools for two different requirements. But if they are both very similar then I will only test one (for now).
So far I've a couple people say there's no real difference in the print and one person say there is a major difference. That leaves me having to test both developers.