Key features hp printer paper a4 pefc certified patented colorlok technology 75gsm colorlok technology the science behind colorlok technology results in more saturated colors bolder blacks and faster drying times during the paper making process a chemical additive is incorporated into the paper to ldquolockrdquo pigments at the surface without this technology paper acts more like a sponge absorbing black and color pigments deep into the paper and away from the surface