Visible light can be a small part of the electromagnetic spectrum but other ranges of wavelengths also occur. Such patterns are known as colors. Red light is on one side of the spectrum, with the longest wavelength. The shortest wavelength is of blue or violet color. White light is a blend of all colors in the spectrum. Wavelength interval of red light is ~ 700–635 nm while blue light range ~ 490–450 nm and is considered main difference between such light waves.