The bulge test is an experimental method to determine the yield behavior and biaxial elastic modulus of thin films. In a typical bulge test, pressure is applied to a free-standing foil. The bulge height h is measured as function of the applied pressure. The initial height h(0) of the bulge deflection must be considered when analyzing interferometric bulge-height measurements as the range of linearly elastic behavior and the magnitude of biaxial modulus enhancement are directly affected by it. Computation of the biaxial modulus over a linearly elastic range to 0.10% strain is shown to yield rule-of-mixtures values for homogeneous Ag/Pd and Cu/Pd multilayer foils. An apparent 500% modulus enhancement for a 1.47 nm Cu/Pd foil is reduced to 12% using an h(0) correction to produce a linear elastic response to 0.10% offset strain. For a 100% enhancement found in a 2.24 nm Ag/Pd foil, the ho correction reduces the enhancement to 51%. Analysis of bulge test results using an ho correction shows that modulus enhancement exists in metallic multilayers, but not to the extent found using a non-linear elastic analysis.