Hi guys! When I started photography I was obsessed with lack of grain, tonal scale and blah blah blah. Well, now I've changed my ways, and I've ignored that last roll of ISO25 in the bottom of the fridge for months. Instead, I've started pushing my film to take photo's in low light situations like get togethers with my friends, and started to enjoy (perversely) that grainy photojournalism look. So, the only real data I've got is Anchell's cookbook, and it worked quite nicely. I pushed a roll of arista 400 to 800, and a roll of tri-x 400 to 1600. My negatives were overly dense, if anything. I realise now that it should be easy to push the arista 2 stops, and the tri-x 3. But anchell stopped with 3 stops in new tri-x. Now I'm curious, just how fast CAN film be pushed and still get a useable image? Iso 6400?, ISO 12800? ISO 25,600? ISO 50,200? How fast is TOO fast? And is there a limit with my D-76/tri-x 400 combo This isn't idle foolishness, I'm really interested! (so it's non idle foolishness) I know I may have to do some personal testing, but I'd rather not re-invent the wheel if I can help it.