I'm looking for a transparent IR paint that will either reflect or retroreflect infrared light while letting the visible spectrum pass though. Usage is AR markers. The augmented reality SDKs use black and white markers and visible spectrum cameras. I don't see a reason why invisible IR markers can't be used instead. For custom markers I'll need some paint.
I think windows are coated with such paints to reduce heat from sunlight in buildings. That's the only thing that comes to my mind.