Abstract: A method of generating an output device control signal having portions representing the content of pixels of an image including at least two types of image content, in which data defining the content of each pixel of the image at a lower, first resolution and a higher, second resolution are passed respectively through a pair of processing paths, one corresponding to each image content type. A binary control signal is generated from the first resolution data in the first path by applying a stochastic screen. The binary control signal resulting from the stochastic screen is adapted to conform with the data at the second resolution, and the output device control signal is generated by combining data from the two processing paths.