Joint NISP out-of-band blocking, including flight model filters, telescope, NI-OA, and QE. The curves are the same as the shaded curves in Fig. 12, with the difference that the blocking was measured at the filter centre only, in wavelength steps of 2 nm. We smoothed the data on a 20 nm baseline to reduce the noise at the lowest transmission levels. The residual optical transmission from the dichroic and the NI-OA at 0.45–0.54 µm (Fig. 12) – shortwards of the VIS bandpass – is suppressed by a factor ≥4 × 10^¯7. Overall, blocking is excellent across the full wavelength range.