This contribution attempts a better understanding and, where possible, an optimization of the components in the image chain of infrared reflectography. It aims to protect the object against radiation in excess of that required for image acquisition, to reveal more of the underdrawing than does the conventional procedure, and to increase the image quality of both the single reflectograms and the assembled mosaic. The automatic acquisition uses a positioning system in which the camera is moved while the object remains stationary. Processing and automatic mosaicing of the digitized reflectograms are done on a computer workstation. The results are demonstrated on a late eighteenth-century painting by J.G. von Dillis. -- CAL