[New aspects concerning exposure factors during direct geometrical X-ray magnification (author's transl)].

The paper is concerned with the use of rare-earth intensifying screens in order to overcome some of the exposure problems during magnification techniques using very small focal spots. Theoretical experiments and tests with biological objects indicate that the use of high intensifying screens under these circumstances is acceptable and useful. A comparison has been carried out between the results of conventional techniques without magnification and magnification techniques using very small focal spots and rare-earth intensifying screens.