RED BLUE GREEN

 
RGB is called the primary color from which different combination are got. This is a additive color in which the three main colors like red blue and green are made to overlap in different ways to produce different array of colors. This theory was there before electronic age, but only in human perception of color. This was based on the Young–Helmholtz theory of trichromatic color vision, developed by Thomas Young and Hermann Helmholtz. This concept was put forth in mid nineteenth century. This method moved from there to photography and to television and now to computers.