A speckle photographic method, which is sensitive to changes of fluid density, is applied for analyzing a compressible turbulent air flow with density fluctuations. Spatial correlation coefficients, turbulent length scales, and energy spectra are determined under the assumption of homogeneous isotropic turbulence. The experiments are performed in a shock tube where the flow is passed through a turbulence grid. Measurements are taken before and after the turbulent regime interacts with the normal shock wave reflected from the tube’s and wall. Amplification of the turbulence intensity by the shock is measured quantitatively and the amplification is shown to be restricted to the lower wave numbers of the spectrum.