Abstract: The invention provides for deciding whether a recording dot is to be printed for the reproduction of scan dots. The scan dots being considered are compiled in an input switching network into groups, for which an arithmetic processor determines the tonal value sum. The arithmetic processor emits a signal, if the tonal value sum exceeds a certain figure. The recording dot to be printed is determined by the presence of the signal in an output switching network. This process is performed successively for increasingly larger areas of the original, that is, for increasingly larger quantities of scan dots.

Abstract: A video memory system is disclosed in which the memory module used to store video data also generates a selection signal that indicates whether the module is a monochrome or color memory module. Memory control logic generates a pixel clock which governs the rate at which pixels of data are output to a monitor, and a load clock which determines the rate at which data is read from the memory module. The load clock is generated at a first rate when the selection signal denotes a monochrome memory module, and at a second, faster rate when the selection signal denotes a color memory module. A shift register receives video data from the video memory module at the rate of the load clock, and outputs that data at the pixel clock rate. The shift register outputs a plurality of bits of the video data in parallel to a video signal generator, which converts the received data into a video signal.