How to create CMYK halftone Images from a color image?

Question

I am working on a project that requires me to separate out each color in a CYMK image and generate a halftone image that will be printed on a special halftone printer. The m

Answer 1

My solution also uses PIL, but relies on the internal dithering method (Floyd-Steinberg) supported internally. Creates artifacts, though, so I am considering rewriting its C code.

    from PIL import Image

    im  = Image.open('tree.jpg')             # open RGB image
    cmyk= im.convert('CMYK').split()         # RGB contone RGB to CMYK contone
    c = cmyk[0].convert('1').convert('L')    # and then halftone ('1') each plane
    m = cmyk[1].convert('1').convert('L')    # ...and back to ('L') mode
    y = cmyk[2].convert('1').convert('L')
    k = cmyk[3].convert('1').convert('L')

    new_cmyk = Image.merge('CMYK',[c,m,y,k]) # put together all 4 planes
    new_cmyk.save('tree-cmyk.jpg')           # and save to file

The implicit GCR PIL applies can also be expanded with a more generic one, but I have tried to describe a simple solution, where also resolution and sampling are ignored.