Isaac Newton was the first to demonstrate through his famous prism experiments that color is intrinsic to light. As part of those experiments, he also divvied up the spectrum in his own idiosyncratic way, giving us ROYGBIV. But why indigo? Why violet? We don’t really know why Newton decided there were two distinct types of purple, but we do know he thought there should be seven fundamental colors. There wasn’t any particular scientific reason he chose the number seven; he just thought it made more sense that way.
In the video above, science writer Philip Ball (author of Bright Earth: Art and the Invention of Color) tells the story of the creation of ROYGBIV. Special thanks to Jackie Lay, who created the animations for the video.