In 1666, Sir Issac Newton took the first step in concentrating on the nature of the spectrum thereby analyzing the various colors. When he passed white light through the glass prism, he achieved the same spectrum just like a rainbow and named Red, Orange, Yellow, Green, Blue, Indigo, Violet – VIBGYOR. He conducted another experiment by passing the spectrum through the glass prism and found the result as the white light. As a next step to know about the complementary colors, he took two prisms and produced different colors on the same spot. The colors that are produced by combining other colors lies between two source colors in the spectrum. Thus, he concluded that color is not in the glass, it’s in the light and white light is the mixture of all the colors in the spectrum. Then he explained the property of illusion which is called as metamerism, which is two colors seem identical when viewed under certain light and different when viewed under different source of light. Later, in the 19th century, Physicist Maxwell James Clerk discovered that the mixing up of three light sources red, blue and green can produce wide range of colors. This is the principle on which the computer monitors work.