The NIST 0:45 reflectometer measures the spectral reflectance factor at an influx angle of 0 degrees and an efflux angle of 45 degrees of colored, nonfluorescent specimens at room temperature, with widths ranging from 3 to 10 cm and heights from 3 to 20 cm and with an uncertainty of less than 0.5 in color difference units. Published in 2008 by John Wiley & Sons, Inc.