As an experiment I shot a roll of Ilford XP2 Super, and cross processed it
in E6 slide chemistry, to get B&W slides. I shot the roll at EI200.
At 200, they look underexposed - quite dark and muddy. I'd estimate under by
about 1 stop, so if I try this again I'll shoot at 100 (In retrospect, I
should have bracketed or shot part of the roll at 200, part at 100 and part
at 50, slap).
The slides also look quite low in contrast. This could be because of being
underexposed, although it could also be a characteristic of the fact that
they are designed to be shot at 400 and C41 processed. I suspect shooting at
100 or 50 will lower contrast even more, so perhaps I should be shooting at
200 or 400, and giving them a 1 or 2 stop push in the first development.
Since the aim is black & white slides, the higher contrast gained by push
processing would probably look more attractive. I also considered the
possibility of using regular B&W chem for the first developer instead of E6
chem, this would require considerable experimentation for times.
Finally, the dyes ilford use aren't black, so what I actually have are
bluish-green tinted images.
Conclusion - it was an interesting experiment, but at $10 for a roll of 24 a
rather expensive one - more expensive than regular slide film, and far more
expensive than regular B&W - I don't think I'll bother again, I'll stick to
colour slides and B&W negs.