Since aerospace coatings and their pigmentation was one of the areas my company was involved in, I was fascinated by a project to make coatings that appeared “white” (totally reflective) in infra-red since some anti-aircraft guided missiles homed in on the dark appearance of most coatings in that range. Although it was not my field, for the fun of it, I was able to use that department’s computer to come up with a coating that was completely black in visible light, but “white” in infra-red. It looked fine until they put it on the roof for sunlight exposure. After a month the blue and green pigments faded and it changed from black to a muddy red. I decided to go back to polymers and let the paint people diddle with their pigments.