The results of computer simulation of the effect of light scattering in a system composed of two heterogenic light-sensitive layers coated on two sides of a transparent base are presented. It has been assumed that the modelled system is irradiated with a directed X-ray beam, while the photographic effect is caused only by the light emitted by the fluorescent screens adjacent to the light-sensitive layers and containing phosphors fluorescing due to X-ray irradiation. The scattered light transpassing the base reaches the opposite light sensitive layer, thus damaging the sharpness of the details. This effect called crossover is disadvantageous in roentgenography. The qualitative dependence of the modulation transfer function of the system on both its geometric and optical parameters was examined. It has been shown that worsening of the image is the stronger the thinner the light-sensitive layers and the weaker the light scattering by single silver halide crystals. This result is surprising since in the case of single-layer light-sensitive systems not suffering from the crossover effect opposite effects are observed.