Abstract: To enable top illumination densitometers in the form of a hand-held instrument to be used not only for measuring light reflections but also for transmission of the test data to a computer, a hand-held instrument is provided comprising an instrument housing with a measuring head and an electronic control unit in the housing for converting the values measured in the measuring plane of the sheet. The housing contains an electronic computer input system connected to the electronic control unit, at least one click knob operable externally on the housing, and a control element for the inputs to the computer input system and a junction box for an interface for transmission of the measured data converted in the electronic control unit into signals to a computer.

Abstract: To enable top illumination densitometers to be used for measuring light reflections on colored control fields of so-called printing control strips, it is necessary to center the measuring openings of such instruments accurately on the control field so as to focus properly. For this purpose, there is provided a hand-held instrument which comprises an instrument housing and a measuring head in the housing, the measuring head having an outer wall, defining a measuring aperture facing the measuring plane and containing a source of measuring light and a measuring light receiver arranged to receive light from the source through light guiding channels.

Abstract: A reproduction camera apparatus comprises a light impermeable housing comprised of four walls and a partition wall intermediate two of the wall whereby the housing is divided into two compartments. A camera is mounted in the housing and a light source for illuminating an original to be reproduced is arranged in one compartment. A carriage is vertically displaceably mounted in the one compartment for displacement along a path in relation to the camera and a holder for the original is mounted on the carriage for movement in relation thereto. At least one of the walls defining the one compartment has an opening in alignment with the displacement path for enabling the holder to be moved into and out of the one compartment. A shielding element is associated with the opening and is displaceable with the carriage, the shielding element defining a slot through which the holder may be moved.