Abstract: A photographic color copying apparatus and an exposure control process includes measuring filters variable as a function of the spectral sensitivities of different copy materials, in particular electro-optical filters. The variable measuring filters are constructed in the manner of Solc filters or Lyot-Ohman filters and include polarizers and electro-optical crystals, preferably liquid crystals.

Abstract: The light emitted by a source of light is passed by means of optical fibers or bundles of optical fibers in lines over a master to be scanned. In the process, an orifice of a disk rotated by a motor sequentially projects the light onto one optical fiber or bundle of fibers leading to the master. The light exiting from the light emitting end of the optical fiber or bundle of optical fiber illuminates the master. On the other side of the master a corresponding optical fiber or bundle of fibers receives the light coming from the master and conducts it to a receiver.

Abstract: The photoelectric scanner is equipped with two circular disks having aligned light passage orifices and mounted on a common drive shaft. Lenses are located in these orifices, the focal points of which are in the plane of the copy master to be scanned. The beam emitted by the source of copying light and parallelized by the condenser arrives through the curved slot of a stationary diaphragm on the lens instantaneously moving through the area of the slot and is focused in the plane of the copy master. From the lens synchronously running on the other side of the copy master, the parallelized beam of light arrives through the curved slot of a subsequent stationary diaphragm and a condenser on a receiving and detection unit with dichroitic mirrors, absorption filters and photoelectric detectors. These detectors convert the optical signals into electric signals, which are conducted to the evaluating electronic device.

Abstract: A exposure control process and a photographic color copying apparatus make possible the optimal adaptation of the evaluation of a copy master to the varying spectral sensitivities of different copy materials, without having to change the measuring filters. The measuring light components of each of the basic colors are detected by a wavelength selective detection device in at least two closely adjacent spectral ranges and the resultant measured values combined into prevailing color extract values.

Abstract: The copy originals are scanned photoelectrically by regions and three color densities are determined for each scanning regions. Additionally, using a high resolution scanning system, a detail contrast parameter describing the detail contrast in the scanning region is determined. The detail contrast parameters are evaluated together with the color densities of the scanning regions for the determination of the copy light quantities. In particular, in the correction of densities, scanning regions with higher detail contrasts are considered stronger than those with lower density contrasts, while color corrections are carried out in exactly the opposite manner.