But a clear, cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more easily than they do red light.
At sunset, the sun appears red (the blue light has been scattered out of that image, too), so the cells of the eye that detect red are overloaded and incapable of registering weaker red signals.
The show started with clothes in camel, black and gray but these immediately gave way to oversized leopard print sweaters, a short suit in traffic light red and a wispy blue dress with a cutaway hem that was paired with drainpipe trousers.
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In two of the trials, the box was dark for 12 minutes and then illuminated for 48 minutes with either long-wavelength red light or short-wavelength blue light directed at the subjects' corneas. (Light color is determined by its wavelength.) The box was dark in a control experiment.
The techniques employed might also help to improve LEDs that produce white light by mixing red, green and blue emitters.
Generally LED bulbs use either a combination red, green and blue LEDs to create white light, or they use a phosphor coating (more common) in combination with a blue LED.
While each contemplated how many houses to buy, Norway offered his lone red property to Russia in return for the third light blue.
The museum was open that day, leaving Mr. van Vliet and his team half an hour to light almost 2, 000 red, white and blue candles on its central staircase.
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By the time we get to the party, for which the Colosseum is bathed in blue light as a backdrop for wire-dancing acrobats dressed in Valentino red, the Felliniesque-ness of it all can bring tears to our eyes.
The display's backlight has nanopatterned grooves that send blue, green and red in multiple directions, letting the LCD show only the light that would be seen from a given viewpoint.
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When a blue light is applied to the area, it activates the drug and shows any abnormal cells as red.
Red, green and blue filters then allow different colours to show within each pixel, but light has to be shone through them for this to happen.
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