(07-13-2025, 09:34 PM)marty39 Wrote: I'm using Gimp 3.04 in macOS. I have a color photo, I desaturate and apply one of the edge-detect filters. The edges come out white on dark, I want black edges on a light background, so I invert colors. I still have white edges on a dark background but they have moved a little. It acts like there is more than one layer and I'm only inverting one of them. So I apply flatten image, and then color invert. Now I get the expected result, dark edges on a light background.
This happens with all the different edge detect filters. It did not happen in Gimp 2.x. Something changed and I want it fixed. Preferably merge those layers, as apparently happened in Gimp 2.x, or at least show the layers in the layers panel.
You are probably having filters applied as non-destructive. Make sure you check the "merge filter" option in the filter dialog. Or click the fx icon next to the layer in the Layers list, and then the Merge active filters down icon in the popup.