Grayscale is a visual art characteristic in which an image is composed exclusively of shades of gray. Each shade of gray represents a specific amount of light transmission. At the lowest intensity, black represents total absence of light, and at the highest intensity, white represents total transmission or reflection of light.
In this definition...
How is grayscale used?
Grayscale originates from non-digital art mediums like painting, sketching, and film photography. In digital art and computer graphics, each pixel represents a different value of the grayscale depending on its intensity. Depending on the project, it’s common for graphic artists, digital photographers, videographers, web designers, and video game developers to use grayscale images at some point.
Numerical representations of grayscale
Modern graphics displays use 8 bits per sampled pixel to create grayscale images. Each pixel displays a shade of gray using a binary format between 00000000 (black) and 11111111 (white).
In RGB models, each color is given a value between 0 and 255. Each color (red, green, blue) is present in equal quantity, meaning R=G=B. The lightness of the shade of gray is directly proportional to the brightness of the pigments, so pure black is represented as R=G=B=0 and pure white is represented as R=G=B=255.
In CMY (cyan, magenta, yellow) models, each shade is assigned a percentage of light reflected from 0 to 100. Similar to RGB models, all three colors are given equal weight. Unlike RGB, however, the lightness of the shade of gray is inversely proportional to the brightness of the pigments. Pure black is represented as C=M=Y=100 in this model and pure white is represented as C=M=Y=0.
Example of grayscale
The two images of Chester below depict an example of a color image translated to grayscale: