Some time ago, I researched and put work into making a Photoshop action that converts grayscale to transparency, but it’s complicated and I still struggle with it for some reason. I checked Affinity Photo again, and it’s utterly easy-peasy with that. Open the file, go Filters> Colors> Erase White Paper. How about that? They have a specific command just for that operation. It doesn’t look transparent in Preview, but it does in Affinity Photo and Photoshop, and it imports to SU as transparent at least when I tried it.
