Make a scan document look flat (remove shadows)

[Pyrrhon]

Hello!

I am new here and need some help!


So my wife made some tea dyied paper that I scanned... Problem is that because of the fluids the paper is not flat anymore.


You can clearly see it on the scan (shadows)

Now I tried a lot of youtube tutorials but it never fit my situation.


Does someone have a tip for me? A solution?

I would appreciate it very much!

EDIT: here is part of the picture attached


Best,
Pyrrhon

[rich2005]

You image has not come through.
Perhaps it is too large for the forum. Can you post it to some storage such as dropbox and post the link here.

[Pyrrhon]

Hi,

I think it fits now, I updated the thread and attached the picture (206Kb)

[Ofnuts]

One solution with Gimp 2.10:

* Filters>Enhance>Wavelet decompose and decompose to maximum level (7).
* In the 'Residual' layer, sample the color (sample average with a marge radius)
* Bucket-fill the layer with the sample color (so tha it becomes a uniform layer)

   

A "softer" but a bit more labor-intensive version is to paint the problem areas of the Residual layer with a large and soft brush.

A more perfect version would also do something similar on the nect to last layer (level 7).

A completely different solution is to do two scans after rotating the paper by 180° in between. Then in Gimp you align the two images and set the top one to "Lighten only". Caveat: this requires an accurate scanner, the scanners of combined printer-scanners are rarely accurate enough.

[Pyrrhon]

Thanks for the thourough answer! I will let you know what worked.

Best
jb



One solution with Gimp 2.10:

* Filters>Enhance>Wavelet decompose and decompose to maximum level (7).
* In the 'Residual' layer, sample the color (sample average with a marge radius)
* Bucket-fill the layer with the sample color (so tha it becomes a uniform layer)



A "softer" but a bit more labor-intensive version is to paint the problem areas of the Residual layer with a large and soft brush.

A more perfect version would also do something similar on the nect to last layer (level 7).

A completely different solution is to do two scans after rotating the paper by 180° in between. Then in Gimp you align the two images and set the top one to "Lighten only". Caveat: this requires an accurate scanner, the scanners of combined printer-scanners are rarely accurate enough.

[Pyrrhon]

Hi,

Wavelet Decompose seems to be a good option, I am going further into it with tutorials!

Thank you so much,

best
pyrrhon