I tried pushing acros a while back when I didn't know what I was doing and it didn't turn out. Recently I've been successfully pushing Tri-X (and the same method, I understand, should work basically the same for Acros at these times and dilutions) with Rodinal 1:100 following these directions: http://www.rangefinderforum.com/foru...6&postcount=47
For future reference, the text:
Quote Originally Posted by horacekenneth View Post
"Films that are shot at speed - 35mm -

Several minute water bath
Rodinal 1:100 - disregard temperature unless extreme heat or cold
1 minute of slow inversions, maybe 20 in 60 secs
3 really hard thumps to dislodge air bubbles, very important
DO NOT TOUCH for 59 minutes, a couple minutes extra will not harm anything(the DO NOT TOUCH is very, very important)
3 water baths then fix and rinse

For medium format, I change the dilution to 1:125 and be sure to use 500mm of solution per roll. Everything else the same.

Pushed film, such Tri-X EI 6400 or Efke KB400 EI 3200...

Several minute water bath
Rodinal 1:100 - disregard temperature unless extreme heat or cold
1 minute of slow inversions, maybe 20 in 60 secs
Every 30 minutes swirl the tank, like you would a glass of wine, for 15 seconds. Do not invert!
Total time - 120 minutes
3 water baths then fix and rinse

That is it.

Some notes...

Expose for the highlights, you will have no trouble with shadow details. Very important to not over-expose as you can quickly lose highlights, if in doubt under-expose a bit.

Negatives will come out of the tank quite 'flat', even when shooting a very high contrast scene. Add contrast when printing or scanning."
I don't know quite how linear push processing times are, but he adds an hour (120 min total) to his push times to get a 4 stop push (so 15min per stop). I was going a little bit over 30min (closer to 45) to do a 2 stop push (just to be safe). Other people will have more objective suggestions, I lean in my developing times.