(09-16-2018, 08:59 AM)carmen Wrote: it kept cropping up at unlikely moments to mess things--especially on the boundary of the alpha channel of the particular layer.
Thanks!
You are possibly using the wrong technique here. The pixels at the edge of objects are a blend of colors, the right things to do is to use Colors>Color to alpha to remove the background color and leave a partially transparent pixel.
One things I have learned over the years is that when Gimp appears to do the wrong thing it is because I'm not using the right technique.