The present invention is directed to an apparatus and a method that characterizes the hiding of coating compositions, such as automotive OEM and refinishes paints. The method is directed to sequentially storing in a computing device hiding data obtained by measuring the color difference (ΔRGB) in reflections of light and dark portions of target areas of a monotonic coating resulting from a coating composition applied over hiding test panel and by measuring coating thicknesses of the monotonic coating that correspond to the target areas, classifying the type of the hiding data, selecting fitting equations applicable to the classified hiding data, fitting the selected equation to match the classified hiding data and locating a hiding thickness on the monotonic coating that corresponds to the threshold value of the color difference at that location to determine the hiding thickness of the coating composition.