I always render my animations in OpenEXR MultiLayer format with various render passes turned on. Is there a way with Blender's integrated paint editor to paint to the render passes of such an .exr file? It seems I can only paint to the "combined" pass, which I am not using at all though. If I try to paint to any other render pass of the .exr file I get the error message "Image requires 4 color channels to paint".
Purpose: Often I just have to correct few pixels in a particular pass of a rendered .exr file. I could also add a complex node network to the compositor just to correct those few pixels, but in such cases editing/painting the pixels of the respective render pass inside the affected .exr file would be much faster.
I saw there is now also a plugin for Gimp, which allows to import OpenEXR files. Has somebody tried it with multi-pass .exr files? Does the Gimp plugin work reliably without screwing something? Because I still need it to be in multi-layer .exr format after editing for the subsequent compositor stage.