Published in Physics World, 5 Nov 2015
Creating dark materials that prevent reflections has become hot competition recently, with Guinness World Records having to keep revising the darkest substance yet created. But depending on who’s asking, the best black may not be the blackest black, as Jon Cartwright discovers
For domestic use, options abound. Pitch black, jack black, lamp black, fine black, velour black, onyx black, blackboard black, black fossil, charcoal, soot, smoke, sinner, black stillness, off black, little black dress, penny black, deep black and – should you want to be left in no doubt – black black. There are probably 50 shades of black, if not more. But sometimes, and especially where physicists are concerned, even the blackest black isn’t black enough.
For many years, NASA has used a black paint manufactured by the international aerospace corporation Lord that has a reflectivity of just 3.5%. That’s several per cent lower than conventional black pigments. Dubbed Z306, it was applied to the Hubble Space Telescope, as well as other NASA instruments, to reduce stray light from the Sun, Moon, Earth and indeed the telescope’s own housing. Without it, all those images of distant galaxies and novae might not have appeared quite so spectacular. […]
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