In this contribution a new efficient modification of a method that enables us to perform the optical characterization of nonabsorbing and weakly absorbing thin films without using the absolute values of the reflectances measured is presented. Namely, this modification is based on determining the values of the wavelengths corresponding to touching the spectral dependences of the reflectances of the studied films measured for several angles of incidence with the envelopes of maxima and minima of these spectral dependences. By means of combining the explicit formulas containing the wavelengths mentioned and the suitable iteration procedure one can evaluate the values of the thicknesses and spectral dependences of the refractive indices of the films analyzed in reliable and precise ways.