I've found that most modern films/developers do very little after a half-hour or so. When I tested max push shadow speed a few months ago I found the 400s grouped pretty close, with HP5 generally 1/4 stop ahead, Tri-x 1/4 stop behind, D400 and TMY in the middle. I've been happy with stuff I've shot at 4000 on TMY (my choice of 400s because I mostly shoot available darkness on 6x9, where grain and acutance are a bigger deal than 1/4 stop of shadow speed.) Stand/other compensating development seemed to offer no shadow speed advantage vs. more mainstream options, but allowed max possible shadow speed without sending the highlights into orbit. T-Max RS developed around 15 minutes offered a tiny bit more shadow speed than everything else I tried (Xtol 1:1 stand, Microphen, Speedibrews, Acufine) but gave truly horribly blown highlights. Microphen gave the best highlight control, but I liked the grain and acutance of the dilute Xtol better.
Originally Posted by kwmullet
I shot multiple sets of step wedge on 35mm, 6 shots per set, opening the camera in the dark to cut a slit between sets. I had a scale below the target that I marked the EI on by moving a piece of black tape. I developed strips from several different films on one reel in whatever the developer du jour was. A little more work, but a lot less film than burning a sheet of 4x5 for each test.
The only film I had trouble with losing speed into the fog was D3200, and it was definitely temperature related. But none of the others did this--TMY and TMZ worked great at 20 minutes stand in Xtol 1:1 at 95F. A little more fog, but resolving the same steps they did at 30 and 45 minutes at 72F.