Clone brush color bleeding/mismatch on bright uniform areas (sky/surfaces) when hardness not 100
GIMP version: 2.10.2
Operating System: 3.18.46 #4
SMP PREEMPT Wed Dec 28 19:36:22 CET 2016 x86_64 GNU/Linux
This bug has existed since the dawn of time, but was fairly more pronounced when the layer had alpha channel enabled. In Gimp 2.10 this ought to be fixed with perceptual gamma blend - unfortunately, it is not. Regardless of pixel precision, clone brush on a bright, uniform area leaves artifacts such as rings or color-bleeding area.
Is the bug reproducible? Always on bright, uniform areas of image; Randomly otherwise.
Reproduction steps:
- Take a properly exposed photo of the sky (example attached)
- Using equalize find an area to clone from and to (eg. for masking a dust spot)
- Use brush with low hardness (in the example a circle of230 pixels and 75 hardness is used)
- When you're unlucky enough, even though on equalize your clone action looked perfect, when you clone on un-equalized area and equalize afterwards, the cloned area will have dark ring on the edge or bright centre. Attaching example.
Example 1: removing the speck at the top using consistent area 45 degrees to its left:
Expected result: Actual result:
Example 2: removing the spot at the center of the image - 32bit integer precision, 60% brush opacity:
Expected result: Actual result:
Example 3: Total madness - 400 pixel brush, opacity 60: