Abstract: An exposed color film having an exposed zone is provided with color areas prior to developing the same by exposing this unexposed zone to light passing through different narrow-band filters. After developing the film, the transmissivities of each of the color areas within a pair of narrow-band ranges is measured. The measured values are compared with known values for various types of film to establish the type of the particular color film. This information is used to adjust the exposures in the different colors when the images on the color film are copied onto a photographic copying material.

Abstract: A method of determining correction parameters for adjusting the amounts of light to which originals are to be exposed in a color copying operation in dependence on the composition deviations of the respective original from a calibrating original involves establishing, for each of a multitude of regions of the respective original, two characteristic values respectively representative of a relationship between the blue and green color values, on the one hand, and the red and green color values, on the other hand, averaging those of the established characteristic values the relationships of which are within a distribution range normally encountered in an image of an object on the original, forming an average from the average values, and ascertaining the magnitude and direction of the correction parameters from the difference between the average obtained from the particular original and a like average obtained from the calibrating original.

Abstract: A method of determining the amounts of light in the basic colors to which an original is to be exposed during a color copying operation to obtain a copy the colors of which are matched in dependence on the image recorded on the original includes the establishment of color density difference functional correlations from values denoting the results of measurements at a multitude of regions of the film strip which includes the original in question. The correlations can then be used for determining the light amounts for most of the originals. Furthermore, the originals are evaluated for discrimination between daylight and artificial light exposures as well as for recognition of originals including color dominants and, in the latter instance, also for ascertaining whether the color dominant was caused by image-important features.

Abstract: The exposed and developed frames of a color film are copied on the basis of information which is obtained by scanning the density of each frame in primary colors as well as on the basis of information which is obtained by imaging a series of gray filters having different densities onto one or more portions of the film outside of the film frames and scanning the density of the image of each filter. The information which is obtained as a result of such scanning is processed by a computer or an amplifier which controls the quantity of copying light in each of the primary colors, either by selecting the interval of exposure of each frame to light in each of the primary colors by controlling the intensity of light in each of the primary colors (if the exposure times in each of the primary colors are identical). The filters can be imaged prior to exposure of frames to scene light and/or shortly prior to development of the film in a processing laboratory.

Abstract: The densities of neighboring unit areas of a color photographic negative are measured in each of the primary colors and the results of measurements are compared with each other to ascertain the dimensions and boundaries of negative portions which exhibit dominant colors. Each such portion is considered in the selection of the amounts of copying light to the extent corresponding to a single unit area. The comparison is carried out by a computer which compares the results of measurements of neighboring unit areas, as considered in and at right angles to the direction of movement of the negative relative to the monitoring elements. A result of measurement is disregarded if it deviates from the result of measurement of a neighboring unit area by less than a preselected reference value which may but need not be different for each primary color.

Abstract: In a single beam photometer the transmitted radiation is modulated in respect of wavelength. As the modulator, an interference pattern filter is used, whose transmitted wavelength agrees in the middle approximately with the absorption band to be measured. The interference pattern filter is either arranged so as to be rotatable in the beam path or oscillates at right angles to the optical axis. The electronic system is tuned to the first harmonic of the interference pattern filter frequency; i.e. the effects of signals of other frequencies are suppressed by the electronics.

Abstract: The two-beam photometer is suitable for extinction measurement on weakly-absorbent samples. The principle of measurement is based on a wavelength selection in either the comparison beam and the measuring beam. In the beam configuration measuring and comparison beam are coincident in space and follow each other periodically. The wavelength ranges in measuring beam and comparison beam is selected by a graded interference filter which is arranged perpendicular to the optical axis and rotatable about this axis. In the zone of the graded interference filter the path of the beam is formed by two narrowly limited beams symmetrically to the optical axis. Both beams are produced preferably by two light sources whose distance may be varied in a direction perpendicular to the optical axis while the symmetry with respect to the optical axis is maintained.