Hello folks.

This summer I'm about to start a scanning task of multiple albums (that is for me and my family).
We are probably talking in the 200+ ballpark range of number of photos, if not more.

I have done similar tasks before, and to achieve best possible result from scanning printed photos I've used the following method:

• Scanning the photography using Vuescan, no filter settings.
• THen a second scan, now using the filter for removing moiré pattern. This also make the image more blurry.
• THen I use Gimp having the second image as a layer above the first
• With Gimp, I then create another copy of the filtered layer, then use the "find edges" and then do the steps in order of making this a mask (similar to alpha channel) of the filtered image.

This results in a composed image where the unfiltered scan is visible, but only in the sharp/edge part of the image. It get better result than filtering alone if the filtering and tuning in Gimp is done right (Gimp is king in this regards).

However as you may understand, it also means some part (along edges) of the image doesn't get fully rid of the moiré patterns.

I therefore ask - do you know if there exist some software or filter (to Gimp) that create a better result? It have to work on Linux, that is an absolute demand - but since this are family photos and I'm doing this for archiving purposes I want to get the best quality as possible for the digital copy.

Thanks in advance

OK.
You missed the explanation of what a Moiré pattern is - I looked it up now, but even so I can imagine different types of artefacts basically representing the physical medium, the photo papaer's structure and how the photo was printed onto it.
Crucial question: Is this the same for ALL your photos?

And I have no idea why the technique you employ does not remove the artefacts from the edges of the photograph.

Some examples might help us understand.

What did your online searches come up with? Surely you're not the first scanning photos & post-processing them with GIMP?

Frankly, if my goal was to preserve as much of the original as possible, I'd just preserve the original, first scan. In a compressed but lossless format.
Do post-processing on copies only when required (sharing photographs).

Agreed.
For the living photos tend to be memory joggers - after they are all deceased, they become family treasures and the original is more treasured for its authenticity. And it is almost certain techniques will develop to enable your descendants to do a better job of restoration without (almost) any effort once they have a digital master.

Well, yes yess yess and sorry for I forgot to say. I do have a folder where I leave all the raw files, it's just not distributed to all family members.

I was trying to keep the post short, and no I don't have any examples for hand by now.

Some examples I found online:

http://www.southampton.ac.uk/~km2/im...rse/moire.html

Here is a thread that shed more info about this phenomen
https://graphicdesign.stackexchange....-the-same-size

A method in Gime that I haven't tested yet
https://www.tutorialgeek.net/2011/06...mp-how-to.html

Searching the 'net for solutions can be hard when you don't get an immediate hit.
Sometimes your first few results just help you refine your search terms; in this case, the term "descreen" popped up in the first two articles. gimp descreen seems to be getting us closer. It would seem that the filters you need might even already be included in a default GIMP installation.

AFAICS, the scanner application might also help.

The first article also says "Moiré patterns are caused by interference between two sets of fine pattern grids, in this case, the scanner cells and the halftone screen in the original. Any scanner will do this, it's simply a fact of physics. Only if you scan at a higher resolution than the printing screen will it not occur - you will simply see the printing dots in the scan."
This, once again, poses the question if your problem is really the Moiré pattern or generally print artefacts?
If definitely the former, I'm afraid the best and probably only solution is a better scanner. May I venture a guess that yours is quite old?

That last article is 10 years old. Not saying it's invalid, but GIMP since has added a selective Blur filter which also might help here.

I know this thread is old, but I found an adequate plugin/method - so I just want to share how to actually solve the problem.

The plugin in question is called Fourier Transform, and is found in a package called G'MIC-QT.

Since Gimp is installed using flatpak, I need to install this package by
After plugin is installed, and Gimp has loaded the image - follow roughly these steps:

• Open the filter dialog : Filters --> g'mic-qt
• Locate the correct filter in three menu : Frequencies --> Fourier Transform
• If slow computer, the preview may take some seconds to complete, just wait it out
• Two major options: Input layers = "Active and below" | Output mode = "New layer(s)"
• Hit "OK". Again, ig you have a large image and slow computer - have some patience
• FILTER FINNISH ITS PROGRESS
• There is now two extra layers being produced by the filter. You shall do some manual editing on the layer whose name contains [FFT Magnitude]
• In general, this layer take form of an area seemingly of white noise with a big + that cross in the center og the image.
• Important: The "+" itself shall not be touched
• Around the center - there will be several white spots in a pattern.
• You're supposed to draw black onto the white spots scattered around. But be careful not painting more than neccesary.
• When you think you're finished putting black on all the white spots, then repeat the Furier Transform filter (no changes in settings)
• Finish - If done correct, the patterns of the image should be reduced to almost nothing.

I did use this method myself in order to remove bee-cube patterns interference (probably not the correct English term) from old family photos I scanned.

1 members found this post helpful.