descreening scans?

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• monNom0

  repeating noise can be eliminated entirely with fourier transforms
  http://www.fmwconcepts.com/image…

  here's a video showing how it works, somewhat. Note sure if this plugin is still available for photoshop, but image magick works for this via command-line
  

  basically, you convert your image to a frequency plot. The repeating frequencies show as hotspots on that plot. You paint out the hotspot and invert the frequency plot and then presto. no more moire!

  monNom 0Permalink

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  • find "Noise Removal - Notch Filtering" in that first link.monNom
  • If you have Affinity Photo, there's an FFT filter under Filters > Noise > FFT Denoise that makes this technique pretty easymonNom

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