LOGARITHMIC GRAY SCALE TEST CHART 16:9

REFLECTANCE

Two 9-graduated counter current gray scales are arranged on a gray background (D=0.75), the

gray scales being graduated logarithmically.

Related to the densities of the gray scales: gamma = 0.45

Related to the reflection values (brightness): gamma = 2.2, that being exactly the reciprocal value

of gamma=0.45.

The output of an optimally gamma-corrected camera yields two 9-graduated counter current linear

step signals. The contrast range of the gray scales is 56:1.

The values of the 9-graduated gray scales are as follows:

The density values are based on a density of BaSO₄ = 0. Two black fields and a white field

are located between the gray scales. The density of the black field is D > 2.4 (reflectance < 0.5 %).

The density of the white field is D = 0.05 (reflectance = 90%)