Abstract: The optical reproduction system comprises an even number (e.g., four) of reflecting surfaces for producing an image rotated 90.degree. relative to an object to be produced, on an image plane that is parallel to the plane of the object. The incoming optical axis and the outgoing optical axis rest on the same straight line.

Abstract: A measuring head, in particular a manual device for the determination of photometric data, includes an optical illuminating device with an aspherical mirror having a groove which extends in an annular manner around an axis of rotational symmetry of the groove, and which, in cross-section, has the configuration of an elliptical segment. The measuring optics to detect the light reflected from a measuring spot forms a round measuring spot on an ellipse at the inlet slit of a monochromator, for which a spherical/cylindrical lens, a first glass rod and a second glass rod are used, the glass rods being provided with cylindrical surfaces, the associated cylinder axes of which are crossed with each other.

Abstract: A measuring head for the determination of the optical reflectance properties of color measuring fields co-printed with color sheets includes an optical illuminating device having two Mangin mirrors and an aplanar system located in alignment with the Mangin mirrors in a central opening. The light emitted by a light source and reflected by the measuring area arrives in a glass rod and is fed through an optical measuring device into a light waveguide, through which the reflected light is fed into a spectrometer for spectral analysis.

Abstract: In the exposure beam path of a copy master which may have various formats, a four element variable objective is provided with stationary rear and front elements and variable intermediate elements. The rear element is arranged in a carousel-like automatic changer and may be replaced together with a master masks. A control device performs, by means of step motors and spindles, the automatic adjustment of the intermediate elements of the variable objective as a function of a particular master format set, in a manner such that the area of the copy master exposed to the copying light is automatically adapted to the master format.

Abstract: Light from a light source reaches a control element via a lens system and a first bar system, is reflected and diffracted there according to local deformations and passed on to a projection surface via a concave reflector, a second bar system and a further lens system. The picture to be amplified is imaged by means of a lens system on a photoelectric conducting layer in the control element. A control layer of the control element is a gel layer and is located between two electrodes in an electrical alternating field that is influenced by the photoelectric conducting layer. The electrode adjacent to the photoelectric conducting layer is formed as a strip grid wherein all strips have the same potential relative to the other electrode. The image to be amplified is exposed on the photoelectric conducting layer in grid-masked form, whereby the grid is disposed orthogonally to the electrode grid. The electrode grid is disposed orthogonal to the bars.

Abstract: An illuminating system has as main components: a light source comprising four low voltage lamps and, associated therewith, reflectors and condenser lenses, a filter unit, an image-producing pair of lenses, a deflecting mirror and light-mixing element made of glass. The condenser lenses produce images of the coils of the low voltage lamps in the central horizontal plane of the filter unit. Images of the condenser lenses are produced by the image-producing lens pair in a light entry face of the light-mixing element. This light entry face is provided with ribbings constituting cylindrical lenses of special dimensioning which effect homogenization of the light in the light-mixing element. In order to reduce light losses, the light-mixing element is composed of two frusto pyramidal element parts and has its smallest cross-sectional area in a middle region in which the smaller end faces of the frusto pyramidal parts are joined to an interposed diffusor disc.

Abstract: A measuring head for a densitometer comprises a light source and an optical system for forming a spot of light of defined size on the surface of an object under test. The optical system guides the reflected or transmitted light, depending on the type of densitometer, from the area of the spot to a photoelectric measuring transducer. The light intensity distribution across the spot as seen by the transducer is weighted to have a bell-shaped curve with its maximum at the center of the spot. The weighting may be done in the optical path from the spot area to the transducer or, as described, in the path between the source and spot area by means of a filter comprised of a plano-convex transparent lens and a plano-concave lens of neutral grey glass. The lenses have the same index of refraction and the same curvatures and are joined to form a plane parallel plate having a maximum transmissivity on its axis, the transmissivity decreasing radially from the axis.

Abstract: A three-component zoom lens in which the middle component is axially adjustable and has a positive refractive power which in absolute terms is at least twice that of the other two lens components. A diaphragm is disposed in the movable middle component. For image position correction, means kinematically coupled to the middle component are provided for the joint axial displacement of all three lens components.

Abstract: A method and apparatus for detecting printing faults or errors in a sample of printed material, such as a bank note, by determining the relative positions of corresponding text on the sample and each of a number of original bank notes, each having been printed by a different printing process used in printing the sample combining the text of the originals optically or electronically taking into account the positions of the text in the originals relative to the text on the sample resulting from superimposition of the text produced by each of the printing process used to produce each original, and comparing the text of the sample with the total combined text. The relative positions of corresponding text on the sample and originals is determined by scanning the sample and originals and obtaining reflectances values at each of a number of corresponding raster points and correlating the corresponding reflectance values to obtaining the relative position values.

Abstract: A head for measuring light diffusely reflected from a surface, the head having an optical projection system for projecting light onto a surface to be measured, and another optical system for collecting the light diffusely reflected from that surface and imaging it on a photodiode. The collecting optics comprise a spherical annular mirror coaxially aligned with an annular transparent planar member which has an annular plane mirror mounted underneath it, the projected light passing through the apertures in the annular mirror, the planar member, and the annular planar mirror. The light diffusely reflected from the surface to be measured passes through the planar member onto the spherical mirror which reflects it back through the member onto the planar mirror which in turn reflects it back through the planar member onto reducing optics which images the reflected light onto the photo-diode.