Peter: my statement 'I rate themn both at ISO 800' had a precise meaning, even if I can't type properly. It means that I have measured them both to be ISO 800. I wouldn't quibble about a third of a stop; I may be inaccurate, they may really be ISO 1000. But they are certainly not ISO 1600.(posted 9188 days ago)If you get good results by underexposing (eg by rating the film at EI 1600) and possibly overdeveloping, of course that is fine.