The image quality of radiographic images from image plate detectors is limited by two factors: first, the quality of the image plate itself and, second, the scanning procedure of the individual scanning device. In this study the impact of the latter on the image quality is investigated. A method to calculate the spatial resolution in the form of the line-spread function and the photostimulated luminescence intensity for various scanning laser beam intensities is presented. Theoretical results are compared to experimental ones obtained from a commercially available image plate. It is shown experimentally that the spatial resolution is reduced with increasing laser intensity of the readout beam, that the detected information shifts spatially and that the response of the photostimulated luminescence does not vary linearly with the intensity of the laser light. The results are explained by light scattering in the phosphor layer of the image plate and information bleaching during the readout procedure. ©1997 American Institute of Physics.