Color Digital Halftoning
Most of our discussion of digital halftoning uses black and white illustrations only. (If you haven't seen the rest of this discussion click here.) The various black and white illustrations show how halftoning is applied to a single channel of color. By showing just one channel, we hope to make the halftoning method more clear. On this page, we've halftoned some color images using CMY color channels, and show the effect of combining the halftoned channels together.
The above grayscale gradient has been halftoned using a dispersed dot method, with equal amounts of CMY colors, which when combined produce a neutral gray.
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| Continous Tone | Dispersed Dot or "FM" Halftone |
The above continuous tone color image has been halftoned using a dispered dot method for each individual color channel.
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| Clustered Dot "PostScript Screens" |
Because these dots are aligned in rows, care must be taken to avoid "moire" or "screen door effect" when combining multiple screens for color printing. Careful adjustments to screen rotation and LPI are made for this purpose.