. . . . "n; and washing the film or layer with a polar protic solvent such as water, methanol, ethanol, propanol, iso-propanol, acetic acid and mixtures thereof, in admixture with, for example, formamide, acetone, acetonitrile, dimethylformamide, N-methyl-2-pyrrolidone, and mixtures thereof to decompose, dissolve and subsequently remove substantial amounts of the Lewis acid component from the pigmented lay" . .