Charting Color from the Eye of the Beholder

摘要

Say the phrase "school bus" to any American, and the image sure to spring to mind is a vehicle of a particular color—a standard yellow that is one of the most easily recognized and evocative product colors in the United States. But how is it that all school buses across the country are exactly the same yellow color? It is neither practical nor feasible for all school buses to be painted with the same batch of paint. Instead, specific color standards exist that assure that all paint manufactured for school buses is within a color tolerance—and that the color stays within that tolerance when the paint is applied to the bus. Where do such standards come from? Are they simply calculations made by a physicist or chemist wield- ing a spectrometer? When it comes to the colors that we use in life, the answer is not that straightforward. It is common to say that certain wave-lengths of the electromagnetic spectrum are a given color, but in truth, it is more correct to say that those stimuli are perceived to be of a certain color when viewed under specific conditions. So without the human observer, there is really no color, and practical standards for color must take this factor of human perception into account.