RGB Color mode : Where colors are there for a web purpose.
CMYK Color mode : Where colors are used for a printing
purpose.
Lab Color Color mode : Where colors are based on human vision
for colors.
Grayscale mode : Where colors are only a gradient of gray.
Bitmap mode : Where colors are either black or white.
Duotone mode : It is using only one color range for the
image, this is used after transforming the color mode for grayscale.
(for ink printing purposes)
Indexed Color mode : for producing 8-bit, 256-color files.
