Does CMYK vs RGB matter for black-and-white printing?

Yes. An RGB grayscale image can carry hidden color data that turns into a muddy four-color black when it is converted for print.

• Convert to CMYK before printing.
• Make sure your grays and blacks use only the K (black) channel.
• Single-channel black prints cleaner and sharper, with faster drying.

Designing in RGB is a common reason black-and-white prints look off, so lock the file to CMYK early.