I have been reading some old comics (and so can you), and that made me remember another of my ugly favourites: Richard Corben. I once heard that he worked directly in the 4 CMYK plates, so I was tempted to do the same.
Unfortunatly Krita and all the fine open source paint- and image-applications have one problem - they do not support CMYK very well, so I simply made 3 layers in Krita and painted with the appropriate colour - black, yellow, Cyan or magenta.
Here is the result starting with the black layer:
Then the yellow: (as you can see I did fuck a bit up and use a too green or to red yellow in my hurry)
Then the magenta:
And last the cyan: (for the finished image)
As people who have tried to make real CMYK or CMY-prints know, the magic happens when you apply the last layer.