Several techniques for the computation of gamut boundaries have been presented in the past. In this paper we take an in-depth look at some of the gamut boundary descriptors used when performing today's gamut mapping algorithms. We present a method for evaluating the mismatch introduced when using a descriptor to approximate the boundary of a device gamut. First, a visually verified reference gamut boundary is created by triangulating the gamut surface using a device profile or a device characterization model. The different gamut boundary descriptor techniques are then used to construct gamut boundaries based on several sets of simulated measurement data from the device. These boundaries are then compared against the reference gamut by utilizing a novel voxel based approach. Preliminary results from experiments using several gamut boundary descriptors are presented, and the performance of the different algorithms is discussed.