The specimen thus appears bright against a dark background.

标本在暗背景下即呈现出光亮。

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A dark purple flower against a dark background instills a feeling of mystery.

黑色背景衬托下的深紫色花朵，给人注入一种神秘的感觉。

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To make sure that the cameras are accurately recording small changes in reflected light, engineers look for a bright light against a dark background to provide a reference point.

为了确保相机准确地记录来自反射光的细微变化，工程师寻找暗背景上的亮光，来提供一个参照点。

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Against a dark background, Lady Thatcher is pictured dressed in black, wearing jewellery and a radiant smile.

BBC: Newspaper review: Margaret Thatcher's legacy considered

The pose and the play of the suspended figure against the architecture are already present, but Miss La La is a dark silhouette against a dim background of dull reds and warm browns.

WSJ: A Dizzying Artistic Feat | Edgar Degas | Miss La La at the Cirque Fernando | By Karen Wilkin

Against that dark background, he often paints in broad, brooding strokes with an ominous cochineal crimson or a dense cobalt blue.

WSJ: Lighting Designer Al Gurdon: The Light Master of Super Bowl Halftime