The dynamic range and radiometric resolution are among the most important indicators of aerial and space images’ fine quality. Gradation properties are of particular importance for aerial and space images, obtained for monitoring and mapping purposes, because the completeness and quality of the information on the earth’s surface objects depend on them, the accuracy of brightness features reproduction of earth’s surface objects. The author discusses various approaches to defining the concepts of dynamic range and radiometric resolution; the most proper definitions of these terms are given in the context of estimating the image’s gradation properties. The expediency of separating the concepts of nominal, actual and useful (effective) radiometric resolution is shown; their definitions are given. Methods of dynamic range and radio-metric resolution numerical estimation based on a histogram are shown. Absolute and relative indicators are considered. The advantages of using relative indicators are shown. Examples of the dynamic range and radiometric resolution evaluation are given basing upon the images obtained by ‘‘Canopus-B’’ spacecraft.