  We present the quantitative investigation of the submicron structure in the
bulk of porous graphite by using the scattering signal in the multi-modal X-ray
imaging with Hartmann masks. By scanning the correlation length and measuring
the mask visibility reduction, we obtain average pore size, relative pore
fraction, fractal dimension, and Hurst exponent of the structure. Profiting
from the dimensionality of the mask, we apply the method to study pore size
anisotropy. The measurements were performed in a simple and flexible imaging
setup with relaxed requirements on beam coherence.
