短文
You go to the local laundromat to do your wash.In the spinning barrel full of sudsy water you load clothes of all colors: a bright red tee-shirt, blue jeans, a green bandanna. The original mix of clothing is as multi-colored as a rainbow. Why, then, does the lint that collects in the lint tray always come out the same color—a bland gray? The answer lies in the way color perception works. Lint is a collection of tiny, loose fibers that come off your clothes due to normal wear and tear. As no cloth, and indeed no single strand of cloth, is perfectly wound, these tiny threads will always be breaking away. Thus were you to load the washer with clothes of only one color—say a uniform purple—the lint would indeed be of that color. In most cases, however, a wash-load is a mixture of hues. The eye, upon examining a closely-knit combination of colors, merges them into a single, generalized sensation. This phenomenon is exploited by painters, who sometimes put tiny dots of different primary colors right next to each other on a canvas to create the illusion of a rich, single hue when viewed all together. If you pull apart a piece of lint carefully you will see that it is indeed composed of multiple colored threads; but as soon as you back away from it, the gray sensation returns. In an idealized situation, where the threads contained all the primary colors in equal amounts, and were not obscured by dirt and other residues, the lint would appear to be white, not gray. But then, if your lint were clean enough to see that effect clearly, you’d never need to wash your clothes.
想象一下你带着换洗衣物到附近洗衣店清洗，呈现眼前的是一个装满了肥皂泡水的大滚筒，这时你把所有要洗的衣服扔下去:鲜红色的T恤,牛仔裤，绿色围巾。这套服饰搭配就像是多姿多彩的彩虹。那究竟是为什么在洗衣机过滤器中收集起来的绒线呈现出来的是不变的浅灰色？ 答案就在人体的色觉是如何工作的。绒线是一些小小的散纤维，他们通常在洗涤过程或者是撕扯中产生。因为没有任何一块布是纺织得十分的完美，所以这些小线头就会到处乱窜。因此如果在洗衣机里搁置的是一种颜色的衣物，例如紫色，那绒线就是紫色。 但大多数情况下，洗衣机里面会混合多种颜色。当眼睛检视那多种色彩的混合物之时，显现出来的是他们共同普遍的色觉感受。这种现象常被画家利用，他们经常在一张画布上把不同的原色挨着绘在一起，而造就出一种整体看来是浓郁单色的景象。如果你小心的扯开一团棉绒，你会发现他实际上是由多种颜色的线头组成。但你把它揉回去之后，看见的又是灰色。 在所有原色的线头数量相等，并且没有被灰尘抑或其他的残渣遮盖的理想情况之下，那些绒线应该是白色的而不是灰色。但是如果你的衣物已经能呈现出那样的效果，就再也没有必要洗衣服啦！