ERO NISP zodiacal light flat-field. This combines the large scales (>80ʺ) derived solely from zodiacal light observed in any NISP exposures with the small and medium scales (<80ʺ) coming from specific LED internal calibration images tailored to each NISP band (only three LEDs were relevant for this purpose: 1160 nm, 1470 nm, and 1720 nm for Y_E, J_E, H_E, respectively). The arbitrary colour scale is used to fully explore the intensity range within each image. The top row displays the evolution of {gain × quantum efficiency} across all 16 NISP detectors at specific wavelengths, highlighting a large-scale pattern that is, however, omitted in the final flat-field in preference to the pattern emanating from the zodiacal light image (bottom left). The completed ERO NISP zodiacal flat-field (bottom centre, for H_E) encapsulates all scales present in the Euclid signal, ranging from pixel-to-pixel sensitivity variations and low-to-medium-sized features (bottom right, showing a detector of 612ʺ × 612ʺ, with a zoom on a 30 by 30 pixels area showing the pixel-to-pixel sensitivity differences), extending to the entire FoV scale. The relative colour range from dark blue to deep red is an intensity ratio of 12% on average across the full mosaic panels and 5% for the variations across the single detector on the lower right.