■Primary colors are sets of colors that can be combined to make a useful range of colors. For human applications, three primary colors are usually used, since human colour vision is trichromatic. There are cyan , yellow and magenta:
■Additive colour describes the situation where colour is created by mixing the visible light emitted from differently colored light sources. This is in contrast to subtractive colour where light is removed from various part of the visible spectrum to create colours.