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+--- Thread: Rings around Brush instead of being feathered. (/Thread-Rings-around-Brush-instead-of-being-feathered)
Rings around Brush instead of being feathered. - Jafaraway - 05-13-2024
I'm new here. Been using gimp for a long time now and sometimes run into the problem I'm currently having. Sometimes when I use one of the standard feathered edge brushes in a transparent layer, the brush's edges are a bunch of concentric circles, instead of being nice and feathered. However if I use the same brush directly on the background, it does look nice and feathered. Is there a setting that fixes this? Or am I doing something wrong?
See attachment. Thank you to anyone who can help with this.
RE: Rings around Brush instead of being feathered. - Ofnuts - 05-13-2024
This is banding, caused by a "slow" gradient where an identical change of values occur at the same time on neighboring pixels and your brain interprets it as a line.
In your case this is worsened by round-off errors and the quantization that happens because you are in a low precision image. If you change the image to high-precision (Image > Precision) (typically 32-bit FP, the other HP modes are rarely useful) and repaint, the result should be a lot better as far as my tests go. But the banding can reappear later, when you will export the image to a low-precision format (JPEG or 8bpc PNG). You can mitigate it using Filters > Noise > Spread. This stirs the pixels a bit and the "identical change of values" no longer occurs on a line so our brains don't perceive it.
RE: Rings around Brush instead of being feathered. - Jafaraway - 05-14-2024
That worked! Thank you so so so much for that information. You're the best