Hello Michael,
I don't know if this fits your situation but it might be worth a look:
http://tech.groups.yahoo.com/group/QuadtoneRIP/message/9205
The workaround that I use is to do all my grayscale image work and printing
in CS5 using the Generic Gray Gamma 2.2 space, that way Photoshop doesn't
muck up the file when it prints it.
Good luck
-Harlan
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