Printing - Black and White in Photoshop CS4 and Photoshop Lightroom - page 277

Step 2: Choose File Print
Make sure that the Print Document space is in Gray.
Step 3: Choose your printer from the Print drop-down menu.
Step 4: Set resolution and image size according to output preference. Center
and scaling preferences can be set from the output settings drop-down menu
at the top right of the dialog box. (See “Set Image Size and Resolution”, page
260 for more details.)