A Mathematical Model of a Contact Screening System.

A mathematical, computer-based model is developed to describe the screening curve of a contact screening system. The model uses Modulation Transfer Function descriptors of the film, Fourier series representation of the contact screen, and large-area density-log exposure data to relate input to output. Seven parameters are used in the descriptors. Experiments with a 2.5 cy/mm (65/inch) magenta line contact screen and two different developers indicate that the screening curve can be computed with a maximum R.M.S. error of 0.018.