Some Frecuency Modulation (FM) or Stochastic screens method are used when printing images on an inkjet printer. This method uses all the same size dots (same drop sizes in my case), but varies the spacing, or frequency of the dots to give the illusion of continuous tone. I'm looking for an algorithm to, using a FM method, build differents colors using 4 inkjets CMYK channels. I'd appreciate some references or information about it.