ROYGBIV
In the Renaissance, several artists tried to establish a sequence of up to seven primary colors from which all other colors could be mixed. In line with this artistic tradition, Isaac Newton divided his color circle, which he constructed to explain additive color mixing, into seven colors. Originally he used only five colors, but later he added orange and indigo to match the number of musical notes in the major scale. This color sequence in reverse is called the mnemonic vibgyor.