Best density maps in low-resolution crystallography with contrast variation

A method is presented of merging experimental diffraction data measured at different contrasts and structure factors calculated with models defined (and refined) at some of these contrasts (or at any other) in order to calculate an optimal density map at any contrast. It is based on a probabilistic approach which uses a joint probability distribution, for each [h, k, l], of the measured intensities and the calculated structure factors.