However, a Pluge pattern always consists of a gray scale with a fixed percentage gradation between the two maximum values white and black. Using the brightness bars, the brightness curve of the display can be adjusted so that the individual gradations are the same from the brightness perception.
The darkest brightness bar represents black and the black level, the brightest white. If the black level or the white levelare not set correctly, then the brightness gradations in the black area are nonlinear. In this case, the gradations that are close to black are displayed too dark, and those that are closest to white are displayed too light.