grayscale mode

grayscale mode used different shades of gray in image. in-8 bit image there up to 256 shades of gray .every pixel of gray scale image has abright ness value ranging from0(back)to 255(white )in 16land 32-bit images number of  shades image much greater than  in 8-bit image gray scale values can be measured as percentage of black ink coverage (o%equal to white 100%to black.