Thomas - High praise indeed - and that image is wonderful. Do you have a preferred soup/developer/recipe for it? Any slower speed versions you've had similar luck with?
When you mention treating it like HP5 - you don't mean use same developers, times, temps do you?
'Been trying to like acros for long exposures, but so far haven't gotten the tones I get from FP4 & HP5. 'Haven't tried Rodinal yet.
I have been using it with ADOX FX-39, which gives very sharp negatives and good film speed. I've also used it with Harvey's Panthermic 777, which is the other developer I currently have on hand; it's more of a fine grain developer focusing on mid-tone and highlight tonality for portrait and studio work.
It's as flexible as HP5+ is, where you'll get nice sharp negatives in acutance developers, and smoother tones in more solvent style developers.
I treat it like HP5+ in that I use the same exposure, the same developing time, and I get very similar negatives as a result. Unless I know which film is which I have to look at the negatives to be able to tell in a print.
Acros is a film very different from FP4 and HP5. Tonality wise, especially when you start to shoot high contrast scenes, will be very different, particularly in the highlights where Acros has very high contrast separation, so if you do contraction development the mid-tones can look a little bit subdued.