Small area measurements of diffuse reflectance from 410 to 700 nm

A technique is described for routinely measuring reflectance of small area nontranslucent samples over the 410-700-nm wavelength range. The new sampling area has a 4.57 nm diam, which is 9.9 times smaller than the sampling area used for conventional measurements with the Cary 17D spectrophotometer. The accuracy and precision uncertainties of the measured reflectances are +/-0.0066 and +/-0.0032, respectively, with respect to the two master standards at the National Bureau of Standards. These values are not significantly different than the corresponding uncertainties obtained using the original sampling area: +/-0.0059 and +/-0.0029, respectively