Ray painted below the waterline with a special anti-rust paint.

雷用专门的防锈涂料涂船的吃水线以下的部位。

《柯林斯英汉双解大词典》

Technicians can date paint from its chemical composition, for example, or X-ray a canvas to reveal what lies below the surface.

例如，技术人员可以通过其化学成分分析其创作日期，或者对一幅画做X光透视，揭示其表面下有什么。

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To find out why, researchers used sophisticated X-ray analyses to determine the exact chemical composition of the paint as it browns.

为找出原因，研究人员用精密X射线分析仪测定了变成褐色颜料的精确化学成分。

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Raeburn was known to use lead-white paint to underpaint the faces of his portrait subjects, which should have shown up clearly in the X-ray.

BBC: X-rays suggest Skating Minister 'not by Raeburn'