Enhanced (001) anomalous scattering by YBa2Cu3O7-d 50 nm films on SrTiO3 substrates with and without a grain boundary versus temperature is interpreted using crystallographic weights to distinguish it from total electron yield and fluorescence spectra. The power of diffraction enhancement is to ascertain the film oxygen composition from the changes in the c-axis, c0 as the film surface is scanned across the grain boundary, and to determine that c0 is constant versus temperature across the superconducting phase transition.