HAM mode places restrictions on the value of adjacent pixels on each horizontal line of the playfield. In order to render two arbitrary colors adjacently, it may take up to two intermediary pixels to change to the intended color (if the red, green and blue components must all be modified). In the worst case this reduces the horizontal chroma resolution from 320~360 pixels to as low as 106~120 (though, for comparison, contemporary technologies like VHS had chroma resolution as low as 40 "lines", roughly equivalent to 80 pixels, but smeared out much more smoothly). This problem is particularly noticeable at areas of sharp contrast (strong horizontal image gradients), where an undesirable multi-hued artifact or "fringe" may appear. Various rendering techniques were used to minimize the impact of "fringing" and HAM displays were often designed to incorporate subtle horizontal color gradients, avoiding vertical edges and contrasts.