This work presents a novel way of generating color differences for synthesizing artistically screened color images. A single color is specified by interacting with the mouse alternately on a constant luminance plane and on a constant hue plane within the LEF color space (the orthogonal space formed by the RGB cube's black-white axis (L) and by its E and F chrominance axes). By interactively selecting a second color point, a color difference is specified. We present a method for extrapolating this color difference throughout all colors of the RGB cube so as to generate consistent color differences, i.e. smoothly varying similar color differences for different colors. The produced artistically screened color patches show that significant luminance differences always generate significant visually perceived differences, whereas significant hue and/or saturation differences do not always generate significant visually perceived differences.