Radiographic examination with x-ray films. These are placed behind the test object. A source of radiation (x-ray tubes, liner accelerator or radionuclide) is positioned in front of the test object. Due to the different absorption of radiation, local differences in the construction of the test object (different x-ray absorption coefficient) can be detected. This makes it possible to find localized defects, such as pores, cavities or inclusions. The film systems are produced in different classes, which differ in granularity (interior blurring) and sensitivity (exposure time), among other things. Detailed film types generally require longer exposure times and vice versa. In principle, a negative image is created on the film. This means that the areas of the image with a high amount of weakening (large amount of highly absorbent material) appear light and areas of the image with a low amount of weakening (low amount of poorly absorbent material) appear dark (Figs. 1 - 3, YXLON International GmbH, shows examples).