The invention provides a method for impeding making a useful copy with an optical recording device of video content displayed on a screen, wherein the method comprises displaying the video content on the screen, illuminating with ambience light of an ambience light source the screen, the ambience light comprises light having a wavelength in the visible part of the spectrum, wherein the ambience light is controlled as function of the video content, and wherein the ambience light is intensity modulated with an intensity modulation having an intensity modulation frequency selected from the range of 40 Hz to 00 Hz.