I try to render some shapes with EEVEE bloom effect and transparent background. I understood that the rendered file output had to be OpenEXR instead of PNG format in order to keep the effect and the transparency.
Nevertheless, when opening the OpenEXR files into the VSE, and adding a background clip, there are always some black contour artifacts around the rendered shapes.
How could I get rid of that and have it done properly from the beginning ? Blender version used is 2.90.
Note : I tried to tick the use alpha box in the compositor. It works better but the colors are changed.