These charts employ time-tested diagonally striped patterns, having a strong visual impact that emphasizes variations in film opacity. They are therefore frequently used for hiding power display purposes, by means of drawdowns or brushouts. Gray stripes in Form 8H-GW provide reduced substrate contrast for use with low hiding power coatings. Spreading Rate Charts (Forms 8H and 8H-GW) are accurately 0.1 square meters (approximately one square foot) in area, and are used in brushout hiding tests at specified spreading rates as described in ASTM Method D 344.