Originally posted by nickthetasmaniac I know you’re talking about EL, not DR, and that’s what I’m skeptical of. I don’t believe you can over or underexpose Delta3200 to the same degree as FP4 (for example) and still retain a usuable image. Do you have a reference that demonstrates high ISO films have better EL?
Other than 47 years of experience having shot everything under the sun including many extinct films like 3M/Scotch 640T or Kodak TechPan, I'd say check out many of @LesDMess posts of his exposure latitude tests and it becomes apparent. Delta and TMax don't quite have the same EL as their other equivalent EI rated emulsions, but even Delta 3200 developed in a standard process using DDX will have a significantly higher EL than FP4+ developed in ID11 at it's rated EI.
Here from Ilford's own data sheet states that FP4+ can be shot at E.I. 50 thru E.I. 200. Of course, we're talking exposure latitude and not how much the film can be push or pull processed, but they are related. That gives FP4+ about +1.3 EV to about -.6EV recommended latitude.
https://www.ilfordphoto.com/amfile/file/download/file/1919/product/686/
With Delta 3200, Ilford's tech data sheets state EI from 400 thru 25,000, although for 'best results' they suggest EI 400-3200. So even with the more conservative numbers, it's +3EV vs. the FP4+ at a range of 2EV for nominal exposures.
https://www.ilfordphoto.com/amfile/file/download/file/1913/product/682/
I would expect that even with the worst matched developers, a higher ISO emulsion will still have a significantly higher exposure latitude than a lower ISO film.