Rivka Galchen’s latest for The New Yorker is a trove of fascinating details about our understanding of color. Galchen opens with the buzziest tidbit: an experiment conducted by a vision scientist who used a laser to stimulate a selection of his own cone cells and glimpse a color unknown outside of his laboratory. In the children’s novel “The Midnight Fox,” by Betsy Byars, the main character daydreams about digging in his back yard and coming across a “brand-new color.” A friend of mine remembers being captivated by this scene, and trying to picture the color. In my youth, I spent an afternoon wondering if I would have been able to imagine the fluorescent yellow of highlighter markers if I’d never seen it.