Descreening or removing moire?

[Ye Olde Guy]

GIMP Version: 2.8.14
Operating System: Windows
GIMP Experience: Basic Level

---

I read there was a Descreening option under Filters\Enhance, but I do not see it in the newest version of the software (3.10.38).

I scan a lot of CD inserts. My scanner has a built-in descreening option, but I've seen others enjoy better performance with filters built in to Photoshop. I was wondering if GIMP has a similar feature?

Thanks, and stay cool out there!

[sallyanne]

The descreen and moire removal are in the plugin GMIC. Either under details or repair

[PixLab]

GIMP Version: 2.8.14
Operating System: Windows
GIMP Experience: Basic Level
[/b]
I read there was a Descreening option under Filters\Enhance, but I do not see it in the newest version of the software (3.10.38).

Indeed, but it's a script-fu which need the fourrier plugin (FFT)
I have it and would have loved to share it but I'm on Linux, only the script-fu will be compatible with your system, and it will not work without the Microsoft's windows file type "fourrier.exe" or "fourrier.dll" or alike.
(maybe rich2005 has it for Windows)

You better off with G'MIC >> https://gmic.eu download, install, restart GIMP, first time launch G'MIC (in GIMP go to Filters > G'MIC_Qt) update filters, then you have plenty way to descreen in GIMP via G'MIC (there is search box)

[rich2005]

I thought there was already a FFT plugin posted somewhere on GimpChat, but I can not find it, so here-again.

This comes from a samj package for Windows and is a 64 bit plugin.
Unzip and put fourier.exe and libfftw3-3.dll in your plugins folder.

Also in the zip is descreen.scm and goes in your scripts folder. This dates back to Gimp 2.6 but I have tried all in a Win 10 / Gimp 2.10.38 and they do work.

When it comes to scanned CD's very difficult to improve a "silver" (not overprinted) surface but inserts should be ok.

[Ye Olde Guy]

Are the GIMP software filters generally better than options found in scanner drivers, such as those for the Epson scanners?

[rich2005]

Are the GIMP software filters generally better than options found in scanner drivers, such as those for the Epson scanners?

Probably not.
---------------

I was told that it is better to scan without any "tweaks" and keep that version as a backup/archive image.
Then apply any editing and save/export as a new image.

All depends on the scanned image. This a stack https://i.imgur.com/wj168ie.mp4
original 8bit RGB / 300 ppi
Descreened using default values, you might improve by adjusting parameters.
Manual FFT which I think is just marginally better than the descreen version.

You have to remember that these processes will degrade the original, make it softer and any sharpening un-do's the effect.