xunrymutcrai
lujvo
x1 is infrared (sensu lato) in color; x1's emitted/reflected light has a wavelength which is longer than that which produces the color red.
Includes radio and microwave radiation, as well as infrared (sensu stricto; a.k.a.: I band). See: "bacyxunre", "xunre", "mutcrai", "skari".