The second hypothesis was that yellow would grant a greater advantage at night than during daylight hours, since it contrasts more strongly than blue does with a dark background. This, too, was true.

Oscar-winning visual effects pioneer Petro Vlahos - who pioneered blue and green-screen techniques used by thousands of movies - dies aged 96.

The effect is so strong, really, that even green, yellow, and orange light pretty much pass uncontested. That blue light goes off in some random direction; some goes up, away from Earth, and some ...