High dynamic range (HDR) display prototypes have been built and used for scientific studies for nearly a decade, and they are now on the verge of entering consumer market. However, problems exist regarding the accurate color reproduction capabilities on these dis-plays. In this paper, we first characterize the image reproduction ca-pability of a state-of-art HDR display through a set of measurements, and present a novel calibration method that takes into account the variation of the chrominance error over HDR display’s wide lumi-nance range. Our proposed 3D octree forest data structure for repre-senting and querying the calibration function successfully addresses the challenges in calibrating HDR displays: (i) high computational complexity due to nonlinear chromatic distortions; (ii) huge storage space demand for a look-up table. We show that our method achieves high color reproduction accuracy through both objective metrics and a controlled subjective study. Index Terms — HDR, display calibration, color calibration 1.