Total spectral response curves, accounting for mirrors, the dichroic element, all optical elements in NISP, and the detectors’ mean quantum efficiency. Top panel: three filter passbands shown together with the approximate emission curves of the five calibration lamps. Bottom panel: blue and red spectral passbands for the first order. The etalon spectrum used for wavelength calibration on ground is overlaid as the grey curve at the bottom. The log-scaled spectrum of one of our compact planetary nebulae for in-flight wavelength calibration is shown in purple (Euclid Collaboration: Paterson et al. 2023). All calibrator spectra are arbitrarily scaled in this figure.