A shadow mask for color picture tubes has a cathode-side surface covered with a heat-insulating layer, an electron reflecting and absorbing layer, and a heat-emitting cover layer. Some of the electrons are reflected while others are absorbed in the cover layer and transformed to heat, but the heat does not act directly on the mask and is emitted into the interior of the tube. Local temperature differences which particularly occur with high contrast pictures and cause partial doming of the perforated mask are reduced.