Abstract: In order to be able to mount a suspended ceiling in places where the space between the ceiling and the overlying structure exceeds 40 mm there is according to the invention used a generally known metal suspension element (2, 3) with a T-iron (4,5).On these T-irons (4,5) there are mounted plaster boards (6) in that on the back of the boards there are glued two metal strips (7,8), i.e. one with a backwardly bent edge (8) overlapping one of the flanges (5) and a metal strip (7) abutting on the flange (5) in the mounted position of the board. It is thereby possible to place the boards loosely and to take them down according to requirements without any need of tools. The structure will allow the mounting of an additional insulation layer on top of the boards (6). At the same time the structure will appear as plane ceiling surface i.e. with concealed support profiles (4,5). This simplifies maintenance.

Abstract: A reproduction camera comprises a supporting frame with an original plane, an objective plane, and a picture plane, the planes being mutually displaceable, and a roll delivering a sheet of light-sensitive material, as well as a conveyor means. According to the invention it is shown how the reproduction camera can be controlled by means of one handle, and according the invention said advantage is obtained by the delivery of a desired length of light-sensitive material from the delivery roll being controlled by means of a first pair of rollers, whereas the transport to the picture plane is controlled by means of an overlying and optionally opaque conveyor band with one or more suction cups. These suction cups are activated in the moment the cutting is performed whereafter the transport to the developer is performed by means of the conveyor band.

Abstract: A method of controlling the contrast by reproduction such as screen reproduction, e.g. screen reproduction of halftone pictures by means of a main exposure and an auxiliary exposure, whereby the density both in the lightest and in the darkest field of the picture and consequently the contrast range of the halftone picture are first measured by means of a densitometer, whereafter the ratio of the lightest spot of the background chosen to the lightest spot of the original is measured and the main exposure is adjusted in response thereto. According to the invention a slider is on the basis of the screen range adjusted in a table indicating the flash percentage versus the screen range and the image range, whereby the flash percentage is automatically measured on the basis of a signal value corresponding to the image range. In this manner references to tables are avoided without using calculating units.