A preparation method for preparing spectrometric determinations of a measurand in a target application using a spectrometer is provided. On the basis of reference data recorded in the target application, a normalized measurand master spectrum with a spectral distribution characteristic of the measurand is determined. On the basis of the measurand master spectrum, synthetic spectra are generated which cover a value range greater than or equal to a value range covered by the reference values. On the basis of the synthetic spectra, information for carrying out the spectrometric determinations, including information comprising a property, a wavelength range, and/or a path length range for an optical path length suitable for carrying out the spectrometric determinations, and/or comprising a calculation rule, with which, on the basis of measurement spectra in the target application, measured values of the measurand are determined.