A Multichromatic Calibration (MC) method of at least a spectral sensor which is one of a list comprising at least a spectrometer, a multispectral sensor, a hyperspectral sensor, a spectral camera, a color camera. The method comprises a. generating a plurality of different multichromatic spectra, wherein i. a spectrum from the plurality of different multichromatic spectra contains light intensity measurable by the at least one spectral sensor and by a reference spectral device, and ii. a spectrum from the plurality of different multichromatic spectra contains light centered around at least two different wavelengths and is configured to be integrated during an exposure time of a single measurement from any of the at least one spectral sensor or the reference spectral device; b. measuring each multichromatic spectrum of the plurality of different multichromatic spectra with the reference spectral device and the at least one spectral sensor; and from all data of the measured multichromatic spectra, compute a transfer function which relates a response of the at least one spectral sensor to a corresponding response of the reference spectral device, without measuring the spectral response of the at least one spectral sensor.