Re: [Gimp-user] Scanned negatives, moire patterns and GIMP?

Thanks to you and Steve for this. I'll make a screen capture available when 
I'm next at my regular computer.
 On a related note; yes the long-range solution will be to get some kind of 
access to a proper scanner.
 -------- Original Message --------

I recently had some 20-year-old color negatives scanned. About half 
scans had moire patterns. My understanding is that moire (in this 
would be caused by contact between the glossy back of the negative and
another flat object such as a glass plate.

Any good transparency scanner comes with a mount for holding the slides 
away from the glass.

If they can't resolve this, what are my chances of solving the problem
with GIMP? I tried a few of the existing filters without visible 
My first Google searches haven't turned up a good detailed tutorial on
moire removal.

There's a G'MIC filter for it. But it depends on the exact nature of the 
pattern as to what's best. I get them when scanning colour books, because 
of the way the books are printed (it's actually unavoidable unless you use 
a "descreen filter" in the scanner driver, but better to do it in GIMP). 
For that, separating into layers and using gaussian blur is often best, but 
another possibility is to use wavelet decomposition and delete that high 
frequency layers. G'MIC has a filter to do that, too.

If you can share a sample I can have a better look.


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