Unless a developer specifically states otherwise, I would almost always use a hardening fixer on negatives. The only exception would be if I were going to intensify/reduce them or have retouching work done. After intensification or reduction I would re-fix them in a hardening fixer. Depending on how they were retouched, I'd re-fix them in hardening fixer as well. Talk to the retouching lab about final fixing before you have anything done.
It's not that you _can't_ use a hardening fixer with pyro, just that you shouldn't. The reason you shouldn't use a hardening fixer is because it inhibits the formation of the stain during the second pass through the developer, weakening the reason you might have chosen to use pyro in the first place.
Basically, if you're going to do anything to the negative after fixing you shouldn't initially use a hardening fixer. After you finish whatever it is you're doing, you should use a hardening fixer to protect the neg. Note to the preceeding, I don't know if there's any advantage to re-fixing a pyro-developed negative after the final wash.
-Chip
|