Achromatic color in photographic works

As a photographic concept, achromatic color refers to white, gray, black and other colors. , only the brightness difference, not the characteristics of cold and warm colors. From white to black, achromatic color can be divided into "five colors and ten grades". Namely: white (including pure white and gray), light gray (including white gray and bright gray), medium gray (including light gray and dark gray), dark gray (including dark gray and dark gray) and black (including gray-black and pure black). Film (roll) imaged only in achromatic color is called black and white film (roll).