Why are radiators white?

Oh I see, so in the range relevant to heaters, black and white paint are similar. In the range relevant to sunlight, they’re different. Thanks everyone! Maybe they should make “cool” black paint, so black cars don’t have to be so hot.

At the risk of ignoring a joke. When dealing with sunlight, white is cool, black is hot. You could make cool black paint, but it’d have to be white, or a mirror.

Simple, good dopers, so that the radiator can be painted any other colour without the base/primer colour changing the hue, just the saturation.
Peter

They do make such pigments. See here, here, and here.

Clever. High reflectance in near infraread gives you the same visible color but significantly lower energy absorption overall.