HL particles at weight frac-tions varying from 15%, 30% to 45% were denoted as HL1, HL2 andHL3, respectively. Each mixture was casted on black and white chartpaper (Captain coating company, Thailand) using a laboratory filmapplicator to obtain a wet thickness of 150 m. After drying at roomtemperature for 48 h, the ratio (%) of hiding power or contrast ratioof coating film on black to white chart paper was determined andanalyzed using a reflectometer, a color guide (BYK Gardner). Foreach measurement, the reflectance of coating casted on black chartwas set as zero and that on white chart area was evaluated. Theaverage contrast ratio was obtained from four different positionsover both black and white areas.