A brief explanation of the topic of emissivity, that gets into the concept of spectral emissivity… a little. It deals with the total emissivity used in radiant heat transfer, but the basic concepts apply at any wavelength. Visit http://www.fuji-piezo.com/emissivi.htm online to read their explanation.
Reference online: http://library.ssec.wisc.edu/publications/resultOnly.php?authorText=Knuteson,%20Robert%20O.&numOfRecs=25&currPage=1. Sample Entries of the 38 records online at the University of Wisconsin Library: 1. Seemann, Suzanne W.; Borbas, Eva E.; Knuteson, Robert O.; Stephenson, Gordon R. and Huang, Hung-Lung. Development of a global infrared land surface emissivity database for application to clear sky sounding retrievals from multispectral satellite radiance measurements. Reprint # […]