I recently was sent a bunch of black and white scans to prepare for the web that are full of moire patterns. My old stand-by trick (rotate the canvas 25 degrees CW and then 25 degrees C-CW) isn't cleaning them up as much as I need, and the source materials are not available for a new scan.
Does anyone have any good techniques for minimzing moire patterns? (I have Photoshop 6)
Hmm... You've tried the standard "despeckle" noise filter then? Too bad they're already scanned in, as I've found even a low-end scanner's "de-screen" setting helps with halftone dots and moire problems quite well...
I just got angry enough to try something new. First I went to L*a*b color and grabbed the lightness channel (the orginal is a black and white so this is all I need). Then I alternated filters: despeckle - dust&scratches - despeckle. I got it pretty good that way, especially when I reduce the size.
Minnapple, thanks for the offer. Look to your sticky mail!
What I'm struggling with now becomes visible after the typical moire becomes unnoticeable. There's a kind of striping artifact - vertical bands about 2 pixels wide, alternating slightly darker and lighter.
I may end up hand selecting the dark bands pixel by pixel and using brightness or lightness to make them come up to a near match. Tedious, but we need this image!