Spacer/extender for titanium dioxide in pigment systems for coatings

A method for applying a coating to a substrate to provide improved hiding efficiency comprising the steps of selecting a coating composition for coatings in a substantially white range having a pigment volume concentration (PVC) of less than its critical pigment volume concentration (CPVC) based on a total solids content of the coating composition, the coating composition having a pigment system including a prime hiding component and an optional filler component, the prime hiding component comprising about 70-98% by volume of titanium dioxide pigment (TiO.sub.2) as one pigment component and about 2-30% by volume of alumina trihydrate (ATH) as another spacer/extender pigment component, the TiO.sub.2 pigment component having a median particle size in the range of about 0.2-0.3% microns and a selected particle size distribution, the prime hiding component taken as TiO.sub.2 alone forming at least a sufficient percentage by volume of the total solids content of the coating formulation in order to exhibit "crowding", the ATH spacer/extender pigment component having a similar median particle size and particle size distribution as the TiO.sub.2 pigment component for by reducing the condition of crowding and thereby developing improved hiding efficiency of the TiO.sub.2 pigment component, and applying the coating composition to the substrate.