16. How do I get a grayscale image in a CMYK document?
Grayscale images that are converted to
CMYK will have a color shift in the final
print. That shift may be green or yellow.
Always check the CMYK values of your
grayscale in the final CMYK document. If
there are other values other than K in your
grayscale image, there is a chance that the
color will vary.
To eliminate all values other than K, use
your Channel Mixer (adjustment layer) in
Photoshop, then click "Monochrome" and
adjust accordingly.