A procedure for the calibration of a micro–goniophotometer is described that enables the analysis of gloss data in terms of the underlying optical properties of the glossy material. Calibration studies are described and calibration procedures are presented, along with a discussion of accuracy and precision characteristics of the current instrument. Examples of analytical applications are described in which the utility of the calibrated device is demonstrated. These examples demonstrate analytical protocols capable of distinguishing between the effects of two key optical constants (n and κ) and the angular distribution of surface facets. In addition, by calibrating the device in separate red, green, and blue bands of light, measurements can provide information relevant to chromatic changes in optical constants and the effects of sublayer specular contributions to gloss. This work is intended provide a tool for imaging scientists concerned with the effects of material properties on the gloss of printed materials. Future work will address the instrumental measurement of appearance attributes of gloss.