The present work reports a detailed experimental investigation of Schopper's formula for investigating the case of a uniaxial nonabsorbing film of barium stearate on a transparent substrate. The required theoretical conditions for the experimental study of Schopper's formulas are well fulfilled for the film studied. The experimentally measured values of the reflectances and transmittances for Ba stearate films are found to be in agreement with the corresponding values calculated from the corrected Schopper's formulas. The experimental values, in general, are found to be in considerable disagreement with the corresponding values calculated by assuming the films to be isotropic. The studies have thus tested the validity of Schopper's formulas and have, indeed, confirmed the films to be anisotropic. Thus, assuming the validity of Schopper's formulas, the refractive indices of several other Blodgett‐Langmuir films have been determined.