Digital BW, The Print

John - The lab that I use for LightJet prints needs the files as RGB's.  I
have a profile from them (they use the same monitor and white point setting
that I do) that allows me to anticipate what the prints will look like, and
I also have a correction curve for them that lets me adjust my files so that
they will print a neutral black and white.  It's also useful to have the lab
print some sort of step wedge so that you can see what the limits will be of
keeping detail in high and low values (K percentages) in an image.