How can I create separate greyscale files from color channels in Krita. I need separate CMYK channels for screen printing.
Image menu has function "Separate Image". It creates the wanted color channels as layers. Keep only one layer visible and close the others in the layers panel.
Export the image as single layer Tiff or PNG, it contains only the visible layer.
It can be useful to save the original with different name and then make the separation and convert the image to grayscale mode to be sure to get a single channel grayscale image, if that's wanted.