Total reflectance measurements of some common surface minerals in the wavelength interval 0.5 µ to 23 µ show pronounced reflection maxima in some regions used for radiometric measurements of planetary surface temperatures. Variations in emissivity in the regions of such maxima could introduce significant errors into such temperature measurements. If measurements are restricted to the windows in the atmosphere of earth the 10-µ to 12-µ interval seems the best choice for radiometry since, in this interval, minerals are most uniformly black.
W. A. Hovis, Jr., "Optimum Wavelength Intervals for Surface Temperature Radiometry," Appl. Opt. 5, 815-818 (1966)