Ultrafine ground limestones were examined to determine their usefulness as paper coating pigments and extenders. Wet-ground limestones varying in particle size were compared to each other and to various coating clays. Starch, styrene/butadiene and poly(vinyl acetate)latices were used as binders, both separately and in combination. Sheets were blade-coated, superor gloss-calendered, and evaluated for optical and print properties. It is concluded that ultrafine wet-ground limestones contribute enhanced brightness, opacity equivalent to that obtained with clay in synthetic binder systems and improved opacity in starch, minor gloss reduction in synthetic binders but unusually low gloss in starch, improved pick strength, titanium dioxide extension up to 25% limestone, and improved high-shear rheology. -- AATA