Spectrometer calibration

A non-transitory storage medium storing computer instructions operable to cause one or more computers to perform operations comprising:

• applying a calibration record to measurements of a sample by a spectrometer module to obtain one or more calibrated wavelength-dependent reflectivity values (RMUT(λ)), wherein the one or more calibrated wavelength-dependent reflectivity values (RMUT(λ)) are calculated based on a wavelength-dependent reflectivity of a known reference material, a calibrated wavelength-dependent intensity value indicative of optical crosstalk intensity and dark noise, a calibrated wavelength-dependent intensity value for a system response of the spectrometer module, and an intensity value measured by the spectrometer module in response to a sample being tested, and
• wherein the calibrated wavelength-dependent intensity value indicative of optical crosstalk intensity and dark noise is calculated based on operation of the spectrometer module in the absence of a sample in a light path of the spectrometer module, or while light emitted by the spectrometer module propagates toward a distant dark target.