August 19, 1994
As is so often the case with truly revolutionary insights, the simplicity of Newton's discovery (about color) causes one to wonder why no one before him had made it.
Edwin H. Land, 1959
In 1660, Isaac Newton passed light through a glass prism, which separated light into a rainbow of colors. He ran that rainbow through another prism and it recombined the colors into white light. He also took various parts of the spectrum and combined them to produce a variety of colors. Any physics textbook will tell you how Newton interpreted these observations, as well as the work that has been done subsequently on light and color. Any artist can tell you which colored pigments have to be mixed to get another color; which was known before Newton. Nowadays you don't need an artist, you can get information on colored pigments at the paint department of your local hardware store.
What you will not find in a physics text book are the experiments on color performed by Edwin Land, the inventor and developer of the Polaroid camera. The experiments that Land performed can be repeated by anyone with access to a camera, two projectors, two color filters, some black and white positive film and the wherewithal to develop it.
What Land did was to take two photographs of a group of objects of different colors (a bowl of fruit will do fine). The photographs were taken using positive black and white film. One picture was taken with a light green filter, and the other through a yellow filter. If you project the black and white slides through the same color filter through which the pictures were taken, and superimpose the projections on a screen, you will see a full-color picture of the bowl of fruit. It doesn't matter what filters you use. You could use a yellow filter and another yellow filter whose wavelength differs by at least 20 Ängstroms. You could use a color filter for one and white light for the other. You don't have to take my word for it, or Land's; this is something that anyone can do. You can find a detailed description and discussion of Land's experiments on color in the May, 1959 issue of Scientific American.
This series of experiments casts doubt on all of the theories of what color is and how we see it. It does more than that; it says that much of what we believe about what color is and how it is perceived is probably not true. Yet, after more than 30 years, Land's remarkable series of experiments will not be found in physics text books. Why would such an important work be ignored? I suspect that the reason that it has been ignored is because it doesn't conform to the concepts that physicists now accept about the nature of color. It is the same reason that Gregor Mendel's work on the genetics of peas was ignored for 50 years -it just didn't fit.
The fact is that while science has made a great deal of progress, human nature hasn't changed a bit. People usually ignore facts that don't conform to their preconceptions. Whether or not we want to admit it, scientists are people.
Many years ago a small airplane made an emergency landing on a highway near Salt Lake City. While the pilot waited for a car to come along to take him to where he could get help, an automobile crashed into the airplane. When the driver of the car was asked if he didn't see the airplane, he replied, "Yes, I saw it, but I didn't believe it."
I don't wonder why no one made the observations that Newton made before he made them. I suspect that someone might have done it, but he didn't believe it. If he did believe it, there was no one to whom he could tell it, nor could he get it published.
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