Method of controlling the contrast by reproduction such as screen reproduction
A method of controlling the contrast by reproduction such as screen reproduction, e.g. screen reproduction of halftone pictures by means of a main exposure and an auxiliary exposure, whereby the density both in the lightest and in the darkest field of the picture and consequently the contrast range...
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Format: | Patent |
Sprache: | eng |
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Zusammenfassung: | A method of controlling the contrast by reproduction such as screen reproduction, e.g. screen reproduction of halftone pictures by means of a main exposure and an auxiliary exposure, whereby the density both in the lightest and in the darkest field of the picture and consequently the contrast range of the halftone picture are first measured by means of a densitometer, whereafter the ratio of the lightest spot of the background chosen to the lightest spot of the original is measured and the main exposure is adjusted in response thereto. According to the invention a slider is on the basis of the screen range adjusted in a table indicating the flash percentage versus the screen range and the image range, whereby the flash percentage is automatically measured on the basis of a signal value corresponding to the image range. In this manner references to tables are avoided without using calculating units. |
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