zone system

noun Photography.
  1. a system for envisioning the values to appear in a black-and-white print and for determining exposure and development, based on a scale of shades ranging from 0 (black) to IX (white).

Origin of zone system

First recorded in 1970–75
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018