Digital BW, The Print

1) Do we know that the "canonical" dpi are controlled
by the printer driver? 

I had thought, for no good reason, that factor was in
hard-wired, irrespective driver.

2) When DPI drops below a certain point I lose certain
tones (including fine details)...this doesn't actually
increase contrast but causes a "punchy" effect, good
for tiny prints...

Black Only does something similar. IMO its coarseness
(abandons tonality between dots) can chop the tonal
spectrum without increasing overall contrast...

...like taking the highs out of music without changing
the mid and bass: sounds great in an old car's AM
radio, less great on a fine system. 

...Black Only and low DPI can make unsharp
images/files seem acceptable in small prints by simply
terminating resolved information before the softness
sets in.

JK