In accordance with an approach suggested by Kissin (J Polym Sci Polym Phys Ed 1992, 30, 1165), a general form of the Beer-Lambert law was employed to estimate the White-Spruiell biaxial orientation factors of the crystalline phase in various polyethylene blown films. Certain assumptions employed by Kissin are invalid for most polyethylene blown films. Alternate assumptions that are based on sound experimental evidence were employed, and the ensuing theory and equations are presented. This technique incorporates into the Beer-Lambert law all possible orthogonal configurations of the polyethylene orthorhombic unit cell with respect to the axes of a blown film along with IR absorption data at 719 cm(-1) and 730 cm-l. Solving the various equations (the Beer-Lambert law at orthogonal polarizations for each band) provided estimates for the mass fractions of all orthogonal configurations of the crystal unit cell with respect to the axes of a blown film. The ultimate biaxial orientation features of the crystalline phase are described as a combination of these orthogonal configurations. The resulting White-Spruiell biaxial orientation factors are in good qualitative agreement with X-ray diffraction patterns for various low- and high-density polyethylene blown films.