Digital BW, The Print

Just as an aside from this general conversation, I recall the discussion
that comes up periodically about whether people can "see separation on their
display between x and y % K" (typically 90, 95 and 100) often in the context
of whether one display is better than another (or whether someone's eyes are
better than another's ;-) ).  Some people would call out that they could,
while others said they couldn't.  Remember that when you look at even an
untagged step wedge on your screen you are looking at a colour managed
object and what you see is dependent on, among other things, the profile
with which the step wedge is tagged and if it is not tagged then your
default (greyscale) workspace.  The separation or lack of separation is
conditional on these settings.  If the document/workspace is tagged Adobe
RGB/GG2.2 then the 95 and 100 patches are very close together in terms of
lightness (much more so than in the case of DG20) - only about 1 L* apart. I
don't think anyone, even those with very good eyes, can practically see a
difference of 1 L* regardless of where it sits on the scale from black to
white, especially if the patches are shuffled and they're asked to choose
the darker or lighter of the two.   If the workspace/document space were
DG20 then absolutely you'd expect to see a visible difference between 95K
and 100K.  They're 5 L* apart and that's enough to be clearly differentiated
on a reasonable display.