Gretag Macbeth color checker chart
From The Glossary of Digital Photography
Also called MacBeth color chart. The standard for measuring and comparing colors in photography, printing, and graphic arts. Gretag Macbeth is a printed chart with different colors and different gray scale levels. There are a total of 24 squares, including pure white, pure black, and four levels of gray in between. Gretag Macbeth is used to determine the color balance of various systems.
