A paint swatch test device includes a transparent or translucent substrate, such as a sheet of polymeric material, and a plurality of different primer coating patches on the substrate. The patches preferably form a grayscale series of neutral white and gray primer patches having stepwise increments in light reflectance values. The patches can also be provided on an opaque substrate. The color suitability and/or hiding power of a topcoat paint desired to be applied to a surface to be painted can be determined by coating the topcoat paint on at least a portion of a surface of the transparent or translucent substrate, providing a grayscale series of patches between the paint coating and the surface to be painted, and observing the appearance of the paint coating where patches are beneath the coating and where patches are not beneath the coating.