Aspects of a micromirror spectrophotometer assembly are described. In one example case, an instrument includes a diffraction grating to disperse broadband light over a range of wavelengths, a detector, a digital micromirror device (DMD) configured to scan through and reflect at least a portion of the range of wavelengths toward the detector, and a base platform having a number of integrally formed assembly mounts. The assembly mounts are formed to align and secure the diffraction grating, the detector, the DMD, and other optical components of the instrument in a predetermined arrangement. The instrument can also include a reference paddle having a reference material for calibration of the instrument, and a rotatable sample tray to rotate a sample placed on the sample tray for measurement.