Printing Grayscale in Adobe Reader
How it worked for me:
Click on Print icon or File-Print.
On the bottom of the Print box, lower left, click on "Printer..."
Print Setup dialog box pops up with a "Do you want to continue?" Yes/No option. Click YES.
In Print Box, click on Layout.
Click on Quality & Media.
Check the Grayscale Printing box near the bottom of the print box.
Click on Print.
I have just learned that in the Mac's Print box under the printer name, it says, "Presets: Default Settings". If I change the printing to Grayscale, as above, I can "Save Current Settings as Preset...". I then named the preset "GRAYSCALE".
Then the next time I print, when I see the Mac Print Box, all I have to do is click on DEFAULT SETTINGS, and under that, GRAYSCALE. 'Saves a few steps.