They photographed a Scottish tartan ribbon three times, once with a red filter, once with green, and once with blue.

FORBES: GPotD: Maxwell's Tartan Ribbon

Then they developed the pictures and loaded them onto three different projectors, one with a red filter over the lens, one with green, and one with blue.

FORBES: GPotD: Maxwell's Tartan Ribbon

Instead of having spectacles with a crude red filter for one eye and green for the other, the Real D system relies on circularly polarised light with one lens polarising the light to the left, and the other to the right.

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Each disc is covered in a transparent plastic coating (either blue, green, yellow or red) which lets daylight filter through.

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The first permanent colour photograph was taken by Thomas Sutton who was working with Clerk Maxwell and is a composite of three black and white pictures, each one taken through a red, green or blue filter.

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In case you don't have your smartphone app handy, the taps are equipped with LED lights to show the water's filter status as well -- blue means clean, yellow means not so much and red means you should probably get a new filter, pronto.

ENGADGET

Philips' solution is to combine two blue and one red element, but use a green phosphor filter to convert one of the blue LEDs to green.

ENGADGET

Colour is added by using three separate arrays, each fitted with a filter for one of the primaries red, green and blue that, in combination, produce a full-colour image.

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Available in Black or Red, it is a stylish camera with a range of creative features including Smart Filter and Magic Frame, designed to enhance image quality along with the shooting experience.

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