How to convert a CMYK image to K?

[B***@adobeforums.com]

Start with a cmyk doc and fill the k channel with the greyscale. Or, convert the greyscale to cmyk > channel mixer > monochrome. Or......

[E***@adobeforums.com]

Change color mode to duotone.

[P***@adobeforums.com]

If you truly have a grayscale image, there will be only one channel. Look at your channels palette to be sure. You most likely also have your Info Palette set to read CMYK, regardless of what your image data actually is.