A Dial Computer for Making Halftones with a Contact Screen.

The main, no-screen and flash exposures to make a camera halftone negative with a contact screen from a black and white original can easily be determined using a simple dial computer. The computer takes into account many variables which have not been considered in the past. These variables include the effect of camera flare. film reciprocity failure and the interdependence of the main and the flash exposures when gray screens having short basic density ranges are used. In addition, the computer can be used to correct originals and tone reproduction can be controlled using a mid-point.