Method of controlling exposure of process camera using sub-exposure and

Abstract

Disclosed are a method of and an apparatus for controlling exposure in halftone photography by calculating a main exposure amount, a bump exposure amount and a flash exposure amount based on basic data peculiar to the combination of a screen and a photosensitive material original data depending on an original in a process camera. The method includes the steps of preparing the basic data and the original data, obtaining a dot image by exposing the original to a photosensitive material through a screen based on the prepared basic data and original data, defining a resultant dot percentage correction value by obtaining differences between dot percentages of the portions of the obtained dot image which portions corresponding to a highlight region and a shadow region of the original, respectively, and the respective desired values, and correcting at least one of the main exposure amount, the bump exposure amount and the flash exposure amount based on the resultant dot percentage correction value and the basic data. The difference between the dot percentage of the dot image obtained as a result of the exposure and a desired value can be used as a correction value, and therefore, a dot image having a desired dot percentage can be obtained without requiring a difficult procedure of evaluating a correction result.