A mathematical filter which improves the contrast response of image intensifiers is derived. The filter is obtained by inverting the point spread function (PSF) of the system. A point spread function which takes into account the spread of light in the image intensi-fier system is proposed using physical arguments. The PSF has two parameters which are the range and the fraction of light which spreads. These two parameters are determined by a least squares fit to the experimentally measured data. The inverse filter is used in the deconvolution of video images. The results indicate that a substantial improvement in the contrast ratio of the system can be achieved by this technique.*