Thursday, November 14, 2013

What Color is an Orange?

Thomas E. Phipps has recently written: “The secret of doing physics lies in the finding of harmless idealizations---those that reveal more than they conceal. There is no formula for it. It is an art…but also a matter of taste, guided by experience.” [1] Not only do I agree, but I see different “harmless idealizations” in different parts of physics.
In the above quote, I could have replaced “doing physics” by “writing nonfiction books for children” and offended fewer people.  With this substitution, author Tristan Boyer Binns seems to have applied Phipps’s philosophy in her little book, What Color is an Orange? [2]
In the space of 32 picture-studded pages (including title page and table of contents), and using simple declarative sentences, Binns has captured a surprising amount of color science. We learn that oranges don’t have to be orange (e.g., no light—no orange; and an orange in blue light looks black). Also, we learn that rods and cones trap the light from an orange, that a prism disperses light into different colors, and a lens re-unites the colors. We even learn about mixtures of paint, ink, and light using three primaries each. The light mixtures reveal their red, green, and blue components when the orange is shown on TV and we see a raster-image detail. In each case, photographs and illustrations (in color) carry much of the message, well beyond the text. For example, in describing the action of a prism the text says “Each colour of light bends a little more than the colour next to it.” Binns doesn’t say which rays refract the most, but it is clear from the picture of a prism refracting light on the opposite page.
There are lots of idealizations. When describing light reflection from an orange, Binns says, “White light falls on an orange. The orange reflects back only the orange light. It traps, or absorbs, all the other colours in the white light.” Another idealization: the colors in a rainbow are exhausted by ROYGBIV. Another: you can get any color by admixing red, green, and blue lights. One can object at every turn. But the picture is intelligible and consistent. It avoids graphs and formulas. And I believe the only numbers in the book are the page numbers. 
Binns is addressing children age nine and over. Could I do better than she did in conveying the subject to this audience? I don’t think so. And she has written many other books whose topics are far from color science---indeed, far from any science. The target audience, however, is probably the same.
I came upon Binns’s book because a Datacolor visitor from China gave it to me during a stay in Lawrenceville. It looked rather strange and not entirely inviting to see all the Chinese text crowding out the feng shui of the page layout. But that just showed something else: within 32 pages, you can even explain the concepts in two languages.
Whenever we teach, we must deal in “harmless idealizations”---in this case, pictures that retain their basic integrity when refinements are introduced. Deciding which idealizations are harmless is no mean feat. It is a matter of taste, guided by experience…

1. T. E. Phipps, Jr., Old Physics for New: a worldview alternative to Einstein’s relativity theory, 2nd ed.  (Apeiron, Montreal, 2012), p. 47.
2. T. B. Binns, What Color is an Orange? Raintree, 2006 (Republished 2007 by Harbin Inst of Tech. Press, as What Colour is an Orange? with inter-line Chinese translation.)

Michael H. Brill

No comments: