This disclosure concerns the determination of low dynamic range image data from high dynamic range image data. A processor determines the low dynamic range image data by optimizing a degree to which the low dynamic range image data satisfies a local contrast constraint and a global consistency constraint. The local contrast constraint is based on a local contrast in a perception space while the global consistency constraint is based on a relationship between points in the high dynamic range image data. The determined low dynamic range image data preserves the local contrast from the high dynamic range image data while also preserving the relationship between points in the high dynamic range image data to a high degree. As a result, the method prevents contrast distortion, halos and artifacts and ordering of level lines (isocontours) is preserved.