Digital BW, The Print

If you're printing BW with color inks that give an infinite 
possibility for tints (R800, for example), here's a tip for viewing 
your prints to determine if they're really neutral (if that's what 
you want).

Take a large Kodak gray card used to determine exposure -- one of 
these should be available at any larger camera store -- and take it 
down to the local craft store. Hold the card next to posterboards for 
sale until you find one that's a neutral gray. Now take that neutral 
grey posterboard home and lay your print on it under the appropriate 
lighting. I then have to walk away for awhile and then look at the 
print laying on the posterboard with "fresh eyes". The surrounding 
neutral gray of the posterboard makes it easy to see if there's a 
tint.

If you do really large prints, a trip to the fabric store is in order 
using the same technique only with fabric instead of posterboard (you 
could hang the fabric from the wall). Or, if you're really 
privileged, a trip to the paint store is in order to paint a tabletop 
neutral grey, or a piece of plywood.