A process for producing images on a photosensitive material comprising a support and a normally positive-working photosensitive layer is disclosed. The photosensitive layer is activated by exposure to ultraviolet light and imaging is effected by means of thermal energy. A mixture comprising a compound containing at least one --C--O--C-- or --C--O--Si-- bond which can be split by acid and a compound forming a strong acid upon exposure is employed in the photosensitive layer and imaging in the activated region is carried out by means of laser or electron beams or with the aid of a thermal printer. The process of the invention is suitable for use with digital techniques and makes it possible, in a simple manner, to employ a combined procedure for imaging the photosensitive material (photocomposing).