https://github.com/LinuxBeaver/GEGL-Dou ... Duel-Color

I made an advance GEGL filter that does both a duel color and duel color glow effect. It is a heavy modification of photocopy.

PLEASE NOTE FOR THE FILTER TO WORK!
This filter requires your layer to have an alpha channel and to prevent color loss you are strongly recommended to apply this GEGL filter on a duplicate layer while fusing it with Gimp blend modes. GEGL's blending operations will work at the cost of color loss. Gimp's blend modes do not have this problem.

It is possible in the near future that glow 2 (AKA the internal dropshadow) will have a checkbox to enable it so the filter will speed up on larger images. Disabling Opacity on glow 2 will hide it. (glow 2) but not remove its node from memory.

https://streamable.com/spzp0o

Video Footage of me using the filter

For GIMP 2.10:
Version for Gimp-2.10.32 Win 64 Bit attached.
Place the file in Gegl plugins in a directory: C:\Users\YourName\AppData\Local\gegl-0.4\plug-ins
If you're missing the plugin-ins folder, create one.

In menu Tools➤ GEGL Operation➤ Double Glow Duel Color Effect