A method of controlling display of a grey level at an associated image point on a matrix display screen. The screen includes lines and columns for which the intersections form an image point. Samples with non-linear proportional light intensity are used to display grey levels, instead of using samples with linear proportional light intensity, by selecting a coding that matches the response curve of the human eye because the eye is more sensitive to brightness differences at a low illumination level than at a high level. Its perception of brightness follows a non-linear law called the gamma correction law which in particular has been modelled by the International Lighting Commission (ILC).