Abstract: A method is presented for spectral reconstruction which comprises first obtaining component concentrations of a series of mixtures, which component concentrations constitute a set of reference values. The spectral value of each member of that series of mixtures is measured at a first wavelength, which spectral value possesses contribution from individual components in the mixture, whose individual contribution is unknown. The spectral values for the series of mixtures are then mathematically cross-correlated with the component concentrations in said series of mixtures, at the first wavelength, thereby obtaining the spectral contribution for said components at that first wavelength. The spectral value of each member of that series of mixtures is measured at the second wavelength, which spectral values are then cross-correlated with component concentrations in the series of mixtures thereby obtaining the spectral contribution for said components at the second wavelength.