Abstract: Aligning measurements of fluorescent spectral radiance factors taken by a first instrument with measurements of fluorescent spectral radiance factors taken by a second instrument, without knowledge of the matrix of bispectral luminescent radiance factor of any sample, includes obtaining a fluorescent spectral radiance factor of a reference sample, measured by the first instrument, obtaining the fluorescent spectral radiance factor of the reference sample, measured by the second instrument, obtaining a fluorescent spectral radiance factor of a test sample, measured by the first instrument, and estimating the fluorescent spectral radiance factor of the test sample that would be measured by the second instrument, based on the fluorescent spectral radiance factor of a reference sample, measured by the first instrument, on the fluorescent spectral radiance factor of the reference sample, measured by the second instrument, and on the fluorescent spectral radiance factor of the test sample, measured by the first ins