06-06-2020, 04:55 PM
That is a big image and in 32 bit FP mode, which should not be a problem. Good choice for a brush - the 50 fuzzy one but the size shown is tiny - only 3 pix - very small for such a large image.
The remainder of the clone tool options are not showing so here is a short, 4 minute demo, of the various options. https://youtu.be/gP5ogpd2RYo
You might see something in that relevant to your image. The offset layer can be set to canvas size using Layer -> Layer to Image Size That might help.
You should really look at the gimp docs as well, https://docs.gimp.org/2.10/en/gimp-tool-clone.html
Otherwise, do not know why you got that strange effect.
The remainder of the clone tool options are not showing so here is a short, 4 minute demo, of the various options. https://youtu.be/gP5ogpd2RYo
You might see something in that relevant to your image. The offset layer can be set to canvas size using Layer -> Layer to Image Size That might help.
You should really look at the gimp docs as well, https://docs.gimp.org/2.10/en/gimp-tool-clone.html
Otherwise, do not know why you got that strange effect.