Color Uncovered. Produced by the Exploratorium. Ipad. Free
Reviwed by Carl Zimmer
Late in his life, Claude Monet developed cataracts. As his lenses degraded, they blocked parts of the visible spectrum, and the colors he perceived grew muddy. Monet's cataracts left him struggling to paint; he complained to friends that he felt as if he saw everything in a fog. After years of failed treatments, he agreed at age 82 to have the lens of his left eye completely removed. Light could now stream through the opening unimpeded. Monet could now see familiar colors again. And he could also see colors he had never seen before. Monet began to see--and to paint--in ultraviolet.
We can turn light into vision thanks to the pigments in our eyes, which snatch photons and trigger electric signals that travel to our brains. We have three types of pigments tuned to violet, green, and red light. Birds, bees, and many other animals have additional pigments tuned to ultraviolet light. Ultraviolet vision has led to the evolution of ultraviolet color patterns. In some butterfly species, for example, the males and females look identical to the ordinary human eye. In UV light, however, the males sport bright patterns on their wings to attract the females. Many flowers have ultraviolet colors, often using them to get the attention of pollinating bees.
While each kind of pigment responds most strongly to a particular color, it can also respond more weakly to neighboring parts of the spectrum. The violet-tuned pigment, for example,can respond wealy to ultraviolet light, which has a higher frequency. Most of us don't get to experience that response, because our lenses filter out UV rays.
But Monet did. With his lens removed, Monet continued to paint. Flowers remained one of his favorite subjects. Only now the flowers were different. When most people look at water lily flowers, they appear white. After his cataract surgery, Monet's blue-tuned pigments could grab some of the UV light bouncing off of the petals. He started to paint the flowers a whitish-blue.
I just learned about Monet's super-vision while reading the lovely Color Uncovered, produced recently for the iPad by the Exploratorium of San Francisco, one of the best science museums on Earth. I don't quite know what to call Color Uncovered. Its iTunes page describes it as "an interactive book that features fascinating illusions, articles, and videos." Yet it feels like an elegantly designed museum exhibit poured into an iPad. Making matters more confusing, you have to go to the education category of the app store in iTunes to find it. When it comes to describing what it is we review here at Download the Universe, words often fail us. Sometimes that's a bad thing, because we're reviewing muddled products of muddled minds. In other cases--like this one--it just means that someone is making good use of several different genres, and melding them into something for which there's no good label.
One challenge to this kind of mixing is that different kinds of presentation work well in different formats. As a science writer, I know that the straight-news style of a story for the New York Times will fall hard on its face in a blog post. If you try to write a book as 20 magazine features, you'll end up with a disjointed mess. Television scripts have their own rules, as do tweets. I encountered the hardest rules of all while working on a museum exhibit. I had to write legends for a collection of objects ranging from whale bones to finch beaks. My instructions basically ran as follows: your audience is made up of ten-year-olds who are running through the room. You have to stop them and explain what they're looking at. And you only have fifty words in which to do so. Go.
Museum exhibits are good training for writing about science on apps. Color Uncovered contains 17 "chapters" covering a wide range of subjects related to color, from optical illusions to food dyes to why dogs shouldn't drive (they can't see stop signs). The text is sharp and concise. It doesn't delve deeply, the way a full-blown book might, but it does deliver instructive facts and stories. While children may get the most out of it, this adult enjoyed it as well.
Museum exhibit designers are also accustomed to combining text with images and interactive experiences, which is crucial for good ebook design. Colors Unlimited contains the classic afterimage illusion, for example, but it uses a built-in timer and other tricks to help you appreciate how your eyes create a color illusion after staring at an image for 30 seconds. It is even so bold as to instruct you to put a drop of water on the iPad screen, so that you can see how a white circle is created by red, green, and blue pixels.
Colors Unlimited doesn't last long. You'll probably spend as much time as you might strolling through a museum exhibit on the same subject. But you'll come away having learned something interesting, and, unlike many museums, Color Uncovered is free. In this case, you get a lot more than you paid for.
Carl Zimmer writes frequently about science for the New York Times and is the author of 13 books, including A Planet of Viruses