Where Red and Blue overlap the Hue "Magenta" is produced. Where Red and Green overlap, "Yellow" is produced. Finally, where Blue and Green overlap, "Cyan" is produced. In the 1950's these three new Hues were called "Secondary Colors", as they were considered impure, being made up from the two pure Hues that produced each of them.

The visible spectrum is comprised of Red, Orange, Yellow, Green, Blue-Green (Cyan), Indigo (Blue), and Violet. These are thought to be the purest colors possible, because they are not affected by a mixture with light of other wavelengths.  In the spectrum the broadest bands are Red, Green, and Blue. Here we may note that only two of the "Secondary" Hues are present in the spectrum, and that they are both narrow in bandwidth.