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+--- Thread: How can I avoid the outlines of removed colors? (/Thread-How-can-I-avoid-the-outlines-of-removed-colors)
How can I avoid the outlines of removed colors? - Zydelum - 06-20-2025
Hello,
With Gimp, I select one or more colors by color > Color tab > Color to Alpha.
Starting with this image:
[attachment=13626]
I can eliminate the yellow and blue without the outlines getting in the way:
[attachment=13624]
From another image:
[attachment=13623]
I can remove the yellow and red, but the old outlines remain:
[attachment=13625]
With Gimp, I can no longer reproduce the first technique and avoid the second technique.
Can someone explain why?
Thank you for your help.
RE: How can I avoid the outlines of removed colors? - Ofnuts - 06-23-2025
Because there are soft edges with "anti-aliasing" pixels, so there are more colors than meets the eye.
See https://www.gimp-forum.net/Thread-Background-removal-or-replacement-on-text-logos-and-other-computer-graphics
RE: How can I avoid the outlines of removed colors? - vitforlinux - 06-25-2025
When I want to remove a color with Color to Alpha, I first make a selection of the color, then I expand it by one or two pixels, then I use Color to Alpha, and the result is clean.
But I have to repeat this for every color I want to remove.
Otherwise Color to Alpha 'eats' the color... even where I would like it to remain.