This is because the aura colour will be changed by the aura of the coloured background or unnatural light.

这是因为气场的颜色会因为气场的背景颜色或非自然光色下发生了变化。

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Low power scanning electron microscope image of tooth surface, computer-coloured yellow on blue background.

牙齿表面的电子显微镜扫描图。

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The two elongated facades display the artwork of artist Anke Blaue, which is a subtle play of coloured strips painted onto a dark grey background.

两个细长的正面展现了艺术家安科的艺术品，这是一个微妙的彩色条状，背景为深灰色。

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Drawn on a piece of paper, the spokesman said it was "full of the pop art motifs we have now come to recognise, including Warhol's signature bright red lips, made using lipstick, and a typically pop art blocked background, coloured with green and orange felt-tip pen".

BBC: Warhol sketch

Like pre-existing blue-screen techniques it involves filming a scene against an aquamarine blue-coloured background.

BBC: Blue and green-screen effects pioneer Petro Vlahos dies

Grids of multi-coloured letters and numbers illuminate the background, itself computer-enhanced to resemble a pitch-black sky.

ECONOMIST: New German photography