1. A method for recognizing materials in an X-ray inspection system, the method comprising: irradiating an object to be examined; recording at least two absorption X-ray images, of the object to be examined, at different energies; mathematically modeling the object by a number of layers assuming a particular material for each layer, wherein an absorption value describes an absorptivity of a layer, the number of layers being less than or equal to the number of X-ray images, and at least one layer being assumed to be a material to be recognized during the inspection; decomposing the absorption value of each layer into a path-dependent factor and an energy-dependent factor; calculating the path-dependent factors for all layers from the absorption X-ray images using the absorption equation; calculating at least one synthetic image from a sum of all layers of the product of the absorption values and selected weighting factors; and evaluating the synthetic image.