Interreflections in a scene can be exploited to improve upon surface and illuminant spectral estimation. In this paper, we present a novel maximum entropy approach to spectral color constancy in the presence of interreflections. Previous approaches employ linear model representations of surface and illuminant spectra. Such representations are not always practical as a database of spectra has to be specified in advance in the corresponding algorithms. The proposed approach has a major advantage over previous algorithms in that it requires only camera sensor responses from the mutual illumination or edge region of a folded surface and from the far from the edge regions to estimate surface and illuminant spectra. We demonstrate the feasibility of the approach while assuming a one-bounce, two-zone model of mutual illumination. We test our approach in both simulation and experiment. In the case of one surface patch in a scene, when the color constancy problem has no solution, we are able to obtain promising results.