If you have ever dug out a photo taken in the 1970s and scanned it to preserve a digital version, you know about the reddish color. Caused by degradation in the dyes used to make the print. Is there an efficient way to do this with a GIMP script or plugin?
I tried several searches before coming here.
You can use per-channel levels modifications.
Would you be willing to share an image here to test out? I have often found that auto levels in GIMP has worked well for me with restoring images that you describe.
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Reptorian, I have never used that specific part of GIMP before. It’s time to tinker!
Terry, give me a bit of time to do so…
Terry, here is the original, as a TIF. (will also upload my work so far, using Color > Levels.)
PS - That shirt was gray.
KC-Color-enlarger-room.tif (6.0 MB)
Wow that looks very good; downloading yer stuff to check it out.
I used Color > Levels and some Luminosity masks…
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Here my own version:
Done in Krita though.
It was a 2 Levels filter process. First one in RGBA mode, and the second one is in monochromatic mode.
Side by side comparison within Krita:
I might have overdone the brightness thing, but a simple adjustment fixes it.
Here, if you copy and paste the filter masks inside Krita onto the image you uploaded, you will get a better result than what I pasted here as I adjusted the brightness. -
KC-Color-enlarger-room-filter-masks-only.kra (12.0 MB)
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That’s interesting and looks good. Is Krita open source or other?
Here is one blending Zbyma72age with mine; Franken-photo.
Open Source.
Here is my edit using auto levels in GIMP. It also includes a slight adjustment of the green curve following auto levels. I have attempted no sharpening or other improvements as I just wanted to highlight the simplicity of color correction with the auto levels option in GIMP.
Krita seems to also have done a similar color fix. I am not sure how simple or difficult this is in Krita.
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Terry, you have a good point about simplicity. My first version had all kinds of convolutions. But, didn’t look as good as the ones posted here by you folks! PS - Which version of GIMP are you using?
I am using GIMP 2.10 but not the latest update which should only have some bug fixes. Auto levels is so quick for those images that it will work on. There are some images where it helps and is the best tool in my arsenal but is still not the great result I want. The supplied image is a good example of where auto levels does a quick fix with a single click.
I download from Partha’s Place because plugins etc are included/ready to go.
With the official downloads, I got tired of having to manually install everything, and then manually edit config or script files to make paths go where they should.
https://www.partha.com/
Fair enough. But Partha hasn’t updated to the latest version, however, that should make little difference. I have either used or recommended his downloads in the past. GIMP is not being developed very much from what I can see. It has most things working fine so that is not a big deal. I mainly edit in darktable, but GIMP is my main program for photo restoration.
It’s a little bit more work, but here’s the step.
- Right click on the image layer.
- Click Add → Add Filter Mask
- Go under Adjust->Levels and click it.
- There’s a icon which has blue, yellow,magnetic. That’ll enable channel independence modification.
- There’s a button under All Channels which will allow automatic adjustment.
- On Shadow/Highlight. Change Method into ‘Adjust per channel contrast’.
- Click Ok.
- Click Ok again.
This gives me this result which is different than my fixes. This method allows you to readjust levels per channel if you want to go back and change things.
Have you tested any of the new AI software for photo restoration? I’ve been using GFPGAN.
https://replicate.com/tencentarc/gfpgan
Ok, sorry for many pictures. Last fun with this picture via Krita:
So, here is auto-level with RGB and manual modification. Sharpen using a Gaussian High and with flat-light blending mode. Then, I have a clone of Group 3, and modify with Level. Within Cross-Channel adjustment to modify alpha based on lightness, and then I assign it to destination in to treat as luminosity mask.
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Thanks for the explanation @Reptorian . @okieman I have tried so AI for restoration and coloring of monochrome images. I am not really convinced it is there yet, but for the worst color faded images turning the image into b/w and then using AI to color the image shows some promise, but has clear limitations such as how can it know the correct clothing color?
The latest version of the GIMP plug-in, even simpler and quicker than the version above from @Zbyma72age
The listing is fully commented, explaining it use.
col-cast-reduction.zip (2.9 KB)
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