Well, Ok Henry, you have a point. You can adjust the exposure that whole 2/3 of a stop you mention. But really, you can do this with any negaive film. I am talking about significant exposure changes, in the order of at least one whole stop, and more like two. This, you cannot achieve on one roll with this- or any other- film. Unless you cut it and develop the two sections differently for the diference in exposure.(posted 8141 days ago)All the other things you mention about this film are perfectly true- and your point about different colors on color paper is of course true and very usefull. Infact, I often shoot chromogenic films and ask the lab to print them warm, and offer my clients a cheap "sepia" option this way.
Yes, it's a good film, esp. for those who want B+W but prefer to drp their film off with the local one-hour lab. And it is of course a great film for students- a lot of my students shoot it!
But a film that you can set (significantly) different ISO's on the same roll? The limitation is that chemical processing is a constant, and so aside from the little bit of lattitude you get- as Henry says, about 2/3 of a stop- from neg. to positive printing, if you want a really faster or slower film, you have to change rolls.