I tried the second swatch using the GIMP using the FFT plugin.
I used a thresholded then blurred copy of the frequency domain image as a mask on a blurred copy of the frequency domain image.
I think I overdid it
Here is your swatch, with my effort at the bottom:
I've used this plugin to remove screening noise from images before. In case anyone wants to try, here is a link to wikibooks explaining how to remove coherent noise using GIMP and here is the link to the fft plugin I used.