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+--- Thread: How to darken / heal bright spots while retaining texture (/Thread-How-to-darken-heal-bright-spots-while-retaining-texture)
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RE: How to darken / heal bright spots while retaining texture - tommik128 - 11-30-2019
(11-26-2019, 12:59 PM)denzjos Wrote: try this :
open the picture
copy the layer
blur 2 to the copy layer
copy the blurred layer (layer 2)
on layer 2 : filters / enhance / high pass (if not, reset to standard values : 4.0 / 1.000)
on layer 2 : colours / brightness-contrast (set contrast 15 / brightness 0)
on layer 2 : set layer mode to linear light
in needed, use filters / enhance / sharpen (unsharp mask)
-------------------------------
An easy way to get rid of the white points, use Qmic Qt :
Artistic / Kuwahara (Iritations 2 / Radius 2)
or
Artistic / Sharp Abstract (Spatial scale 2.4)
or
Repair / Recursive Median (Median radius 4 / Repeats 2)
or
Repair / Remove hot pixels (Mask size 4 / Threshold 10)
As I said, filters redraw the texture. It kinda changes the overall look and sharpness of the picture.
RE: How to darken / heal bright spots while retaining texture - denzjos - 12-01-2019
The full information was not on the original picture you scanned because the original picture was set on paper with a halftone dot proces print. Between the dots one can see the color of the paper (white in your picture). If one try to remove the white dots is the only solution to grab information (colors) from the pixels arround the white dots. The result is a less or more blurred picture because in most cases the colors who filled the white dots are a result of one or more colors (included in this case, the white dots). Make a few layers with the different solutions I mentioned in the post and try to get a acceptable result by playing with the different layers opacity. You can not restore the picture to the original drawing that was made for the magazine because information of the original drawing was lost by printing the magazine.
More information : https://en.wikipedia.org/wiki/Halftone
RE: How to darken / heal bright spots while retaining texture - rich2005 - 12-01-2019
You can reduce the effect of half-toning using a fast-fourier-transform (FFT) plugin. I use a separate one but there is one in the gmic plugin http://www.gmic.eu . I did this demo for someone recently. https://youtu.be/pBTlcdMJpqQ about 3 minutes duration.
akovia gave a reference where FFT was mentioned: https://fanart.tv/tutorials/quick-guide-scanning-covers/
Has to be fairly aggressive for that image so it does give a result that is a bit on the 'soft' side. Maybe go around the title text with an outline to make it stand out. Something like this (quick edit, you can do better) https://i.imgur.com/20mbpec.jpg
RE: How to darken / heal bright spots while retaining texture - denzjos - 12-01-2019
Nice job with the fournier rich2005, thank you for the tip. I've worked on the original picture with the fournier filter and then used 2 Script-Fu Sharpness filters :
Script-Fu / Sharpness / Sharper / High-Pass Sharpen (radius 10)
Script-Fu / Sharpness / Sharper / Smart Sharpening (Amount USM 2 / Radius USM 2 / Find Edge Amount 1,5)
[attachment=3517]
As rich2005 mentioned, try different settings for the filters, you always get another (better or worse) result. If you are satisfied withe a result, make notations concerning the settings and filters. You may need them later on pictures with the same error. Succes !