Happy Monday, everyone. I'm off to a great start.

I accidentally exposed a roll of TMAX 400 at 100 ISO. I usually shoot 100, and that's what my light meter was set for. I'm an idiot. What can I say.

Can anyone tell me how much I should alter the processing to compensate? I know I need to reduce development time, but I don't know how much. Should I develop at the recommended time for TMAX 100? Or, should I reduce development to somewhere between the recommendations for 400 and 100?

This problem has spurred another question: I've tinkered with altered development times before, but nothing this drastic. In researching this problem, just now, I read that TMAX is not good for push or pull processing. I'm trying to learn a little about the Zone System. Should I be using a different film?

I use D-76, if that matters. Any advice is appreciated.

Thanks,
Paul