Gretag Systems, Inc.

Re-Fer Ag

Eidgenoessische Materialpruefungs- Und Forschungsanstalt Empa

Rolf Bronnimann

Christa Strobel

Harald Maxeiner

The copying light of a source of copying light is attenuated in areas using a mask with different density ranges to influence the density by areas of a copy to be produced from a copy master. The appropriate area of the mask is selected by analyzing a location dependent density variation of the mask stored in matrix form in a computing and evaluating unit by predetermined criteria. A photographic copying apparatus associated with the process includes an exposure station with a mask mounted on a slide. The slide may be displaced in response to control signals determined and generated in the computing and evaluating unit. The slide is displaced in a plane parallel to a transport plane of the copy master in the beam path of a source of copying light.

Exposure control process and photographic copying apparatus

The copy master is illuminated in scanning sections located along scanning lines and measuring light coming from the scanning sections of a scanning line is spectrally decomposed and subsequently passed onto a photoreceiver line coordinated with the scanning line involved. Along this photoreceiver line photoreceiver groups sequentially follow each other, each group being assigned to the spectrum of a scanning section of the scanning line involved.

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Buchs, Switzerland

Rolf Bronnimann