4 color image convert to cmyk BLACK ONLY

[T-Rex]

Hi,

I have another method, if it is a color original:

Go into Channel Mixer and turn the CMY channels each to 0%. Go into the Black channel and mix the visually most-pleasing mix of each of the CMY channels into that.

I use that method for clipped photo shadows as well, getting the original shadow out of the background and cleaning it up.

[colorblind]

By copying your grayscale and pasting it into the black channel of your CMYK document should leave you with the exact same values as your grayscale document, unless it's got to do with your color management policies on your newly created documents.

Hope this helps.