noun
: a series of regularly spaced tones ranging from white to black through intermediate shades of gray used as a reference scale for control purposes in both color and black-and-white photography
noun
: a series of regularly spaced tones ranging from white to black through intermediate shades of gray used as a reference scale for control purposes in both color and black-and-white photography
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012