Archived posting to the Leica Users Group, 1999/10/25
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]This recommendation has always bothered me as well. I find that the stated ASA speed is often a tad higher than my desire for shadow detail and hence shooting TMAX at 800 and developing at the time for 400 worsens the situation. As has been recently stated on the list, an excellent way to calibrate your film/dev/temp/aggitation degree combo is to shoot an 18% grey card, and then shoot each stop down. 5 stops underexposed should give barely noticible density on the neg. 6 stops down should give no density (i.e. indistinguishable from the edges). Assuming you start with ISO 400, if you only can seen 4 stops down then your effective ISO is 200. If you can see 6 stops down then your effective ISO is 800. You can calibrate contrast by the amount of aggitation, more aggitation gives more contrast (highlight density). So, you can increase the development time until you get the proper shadow detail, at a given ISO, and then shake more if the negs are missing highlights (i.e. thin) or relax a bit if the highlights are blocking. Kodak recs generous aggitation with Tmax developer, BTW, Ilford less with DD-X. (poor man's zone system :-)) Jonathan Borden > > > I've been using & processing TMax 400, rated at ASA 400 for the past few > months & really like the results, but now would like to try a roll & push > the speed to 800 & see what the film is capable of. In checking Kodaks > recommended processing of the film at ASA 800, I see it does not > differ from > rating it at 400. Does anyone out there use this film at ISO 800? It seems > to me the negs would come out a little thin processed like I do at 400 if > the film is shot at 800. I process the film at room temperature, > which in my > apartment comes out at 74 degrees & at ISO 400 is 5 1/2 minutes with TMax > developer. > > Thanks. > > >