时差N小时 如何利用X射线检测米勒作品?(下)

The artist–or even another painter–may have painted over original layers of paint for many reasons.

艺术家或另一位画家可能在原画中继续作画的原因有很多，

Perhaps an arm didn’t look quite right, or an entire figure was painted over.

可能是一只手臂看起来不太对称，或是整幅画的颜料过于厚重。

Because paint easily absorbs long wavelength¹ X-rays, they’re most commonly used to reveal² hidden paintings.

由于颜料易吸收波长较长的X射线，因此经常会被用来显示隐藏的画作。

First, X-ray film is placed directly³ behind the painting.

首先，将X射线胶片直接放在画作后面。

When X-rays pass through the painting from the front, they’re absorbed by different types and thicknesses of paint to greater or lesser⁴ degrees.

当射线从前面照射画作时，它们会被不同型号和厚度的颜料吸收，吸收的程度各异。

For example, paint made with lead or cadmium absorbs more of the X-ray than paint made with chromium or cobalt.

例如，相比由铬和钴制成的颜料来说，铅和镉制成的颜料能够吸收更多X射线。

And thick paint absorbs more than thin layers.

同时，厚重的颜料层比薄的颜料层更易吸收X射线。

The resulting X-ray film may reflect a ghostly image not only of the painting visible⁵ on the surface, but also the painting hidden beneath.

最后，X射线胶片不仅会显示出表面图画的影像，还有隐藏其中的画像。

1 wavelength   

n.波长

参考例句：

• The authorities were unable to jam this wavelength.当局无法干扰这一波长。
• Radio One has broadcast on this wavelength for years.广播1台已经用这个波长广播多年了。

2 reveal   

vt.揭露，泄露；展现，显示

参考例句：

• The journalist did not want to reveal the identity of his informant.那个新闻工作者不想透露消息提供人的身份。
• Differences will help to reveal the functions of the genes.它们间的差异将会帮助我们揭开基因多种功能。

3 directly   

adv.直接地，径直地；马上，立即

参考例句：

• I will telephone you directly I hear the news.我一听到消息，马上打电话给你。
• She answered me very directly and openly.她非常坦率地、开门见山地答复了我。

4 lesser   

adj.次要的，较小的；adv.较小地，较少地

参考例句：

• Kept some of the lesser players out.不让那些次要的球员参加联赛。
• She has also been affected,but to a lesser degree.她也受到波及，但程度较轻。

5 visible   

adj.看得见的，明显的，显然的；n.可见物

参考例句：

• It is a visible star in the sky.这是一颗在天空中可见的星星。
• The warning lights were clearly visible.警示信号灯清晰可见。