[A neglected technique for reproducing slides (author's transl)].

Duplicating x-ray films is a matter of interest to all physicians, even if they are not radiologists. The impossibility of a direct reading is a major drawback of reproduction in the form of slides. By contrast, a transparency is an irreplaceable teaching tool. Contact printing of slides on counterpart film is a process within the reach of all departments of radiology. In one single step, this process gives a plate of 100 transparencies on counterpart film costing about 2.20 dollars.