Checkerboard Charts/Spreading Rate Charts
One of the earliest hiding power test surfaces was linoleum with a black and white checkerboard pattern. This was soon replaced by sealed paperboard charts of which Forms 10H and 10H-BG Spreading Rate Charts are typical examples. Designed for brushout tests at specified spreading rates, such as in ASTM Method D 344 and Canadian 1-GP-71, they are also used for drawdown applications like their smaller counterparts, Forms 10A and 10B. Black and gray squares in Form 10H-BG provide reduced contrast for testing coatings with lower hiding power.