Yellow is the most luminous of all the colors of the spectrum. It’s the color that captures our attention more than any other color. In the natural world, yellow is the color of sunflowers and daffodils, egg yolks and lemons, canaries and bees. In our contemporary human-made world, yellow is the color of Sponge Bob, the Tour de France winner’s jersey, happy faces, post its, and signs that alert us to danger or caution. It’s the color of happiness, and optimism, of enlightenment and creativity, sunshine and spring. Lurking in the background is the dark side of yellow: cowardice, betrayal, egoism, and madness. Furthermore, yellow is the color of caution and physical illness (jaundice, malaria, and pestilence). Perhaps it’s no coincidence that the sources of yellow pigments are toxic metals - cadmium, lead, and chrome - and urine.