Can I have grayscale images in my art?
GRAYSCALE ON SCREENGRAYSCALE AFTER PRINT Grayscale
In the final CMYK document, do not forget to check the CMYK values of your grayscale. For other values other than K in your grayscale image, there is a possibility that the color will differ.
To eradicate all values other than K, in Photoshop, use Channel Mixer (adjustment layer) and then click “Monochrome” and regulate accordingly.