...and yet another technical thread veers into speechmaking about learning to use our tools. Yes, yes, we all know this obvious truth regarding virtually any endeavor. It does not mean it is a waste of time to talk about the differences in materials when a question is posed. I especially think it is important since much of what is said is either incorrect or misleading.
Yes it is true some of the differences between materials are immaterial, and should pobably be ignored. And yes how we refine our technique and work with our materials is extremely important. But there are sometimes characteristics which are quite different, not good or bad, but different, and there are implications when printing. Again, not good or bad, just characteristics worth understanding.
For example, everybody talks about grain masking in Pyro negatives, how the stain makes grain less apparent. True, but the context is usually wrong. The grain masking effect reduces the prominence of grain relative to non-staining high acutance developers. Even with stain and less silver in them, Pyro and Cat negatives are still noticeably grainier, sometimes a lot grainier (depending on the formula) than a negative developed in XTOL. Sandy King himself has written about how if fine grain is important to someone using small or medium format they would probably be happier using XTOL than PMK or Pyrocat. The tiny differences, if any, in highlight tonality are outweighed, and can be compensated for with skill in printing.
Just one example.