Originally Posted by jdef
I guess that you are one of the very few that I have encountered that relate that HP5 is a film that is capable of high DRs sufficient for expansion with Azo, Pt-pd and other alternative processes. I don't know what experience you have had with negatives that you have exposed, developed and printed to a high DR. I am talking of density ranges above 1.50 (High density minus low density...not minus film base plus fog).
Having had a fair amount of experience with ABC, I would not recommend it to anyone as a developer of choice when one is developing negatives for enlarging. That is unless you want tons of humungous clumps of grain. The grain that I mention is apparent when one enlarges 200 asa 4X5 negs to anything larger then 8X10 prints on a condensor enlarger. Perhaps a diffusion light source would allow a slight amount of enlargement increase over condensor.
HP5 is typically known among photographers requiring high DR negs as a film best suited for contraction of high contrast scenes...not expansion of low contrast scenes. That is just the nature of this material.
For those wanting increased contrast there are far better choices then HP5. Tmax 400, Efke PL 100, and FP4 are all better choices.
As a side note, over exposing film is not the answer to gaining increased contrast in fact if one is placing low values at Zone IV and V then the density range available on a given film is compromised to a very real extent. Over exposing film directly leads to reduced density range (contrast).
Having said that I will say that ABC will show a decrease in effective film speed...even when developing to high density ranges. Other staining developers do not show that same tendency.