Hi Dmitiri, many thanks for your review. Your comments on the dynamic range are very interesting because I think I found the exactly the same while doing film testing with a densitometer.
I wanted to find the base ISO (Zone I) and development time for a Zone VIII exposure of Delta 400 in Adox XT3 (similar to Kodak XTOL). I used replenished stock (i.e. not 1:1 / one-shot).
Using my setup and development practices, and contrary to ‘popular belief’, I found a base ISO of 320. So, at least in my case, XT3 is not speed enhancing for Delta 400. This can be due to a difference between XT3 and XTOL, or my choices and development routine, but it could also be that in another developer, like HC110, I will find an even lower base ISO for Delta 400, e.g. 250 or even 200.
I didn‘t find a lot of information on the Net that suggested the same, but when I read your consideration of the Delta 400 characteristic curve, you‘re essentially saying the same: overexpose Delta 400 (a little bit), and try to control contrast e.g. using a colour filter (for FP4+ I practically always use a Hoya Y2 Pro).
I would like to add that an adjusted development time can be used to not blow out the highlights. I didn’t complete my testing of Delta 400 for all EIs, but for EI 320 I think I will end up at 07:30 min. in XT3 stock. My routine is: replenish 70 ml per 135 or 120, 20 degrees Celsius, with gentle inversion initially for 30 sec. followed by 3 gentle inversions every minute (max. 10 sec).
