We develop an imaging colorimeter for measuring tooth color that is based on two exposures with a digital camera using two different filters. Our work continues that reported by Wu et al.¹ We describe new procedures for alignment and calibration of the system. We also consider three different sources of illumination. We propose two approaches to estimating tooth color information from the acquired camera data, both of which employ linear regression. In the first approach, we estimate CIE XYZ coordinates of the tooth under a preselected illuminant. In the second approach, we estimate the spectral reflectance of the tooth, thus enabling us to predict tristimulus values under any illuminant. Finally, we present results from in vivo measurement of subjects' teeth. In this case, we achieve mean and maximum errors of approximately 1 and 2 delta–E_a*b* units, respectively.