The results of using the inhomogeneous models as well as technique for their error determining are demonstrated. An inhomogeneous profile error was presented as set of 'error profiles'. The homogeneous, linear and exponential models of profiles of N and K were used for searching. Initial colloid SiO2 film, after its heating and exposition in air as well as after reactivating was studied. The layers with decreasing PbO component were found on surface of PbO-SiO2 glass. Graded N and K profiles of In2O3-SnO2 film, used as transparent conducting electrode, were determined by multiangle ellipsometry at wavelength of 632.8 nm.