Average deviations () versus the number of photons or rays that are computed at each wavelength (N) are shown for the total global SEDs and Y image slices. The images are for the most challenging case of τ_z(1 μm) = 10 and illustrate the qualitative impact of increasing N. Plots and images are shown for θ = 0°, 90°, and 180°. The dotted horizontal lines give the 1% (global SED) and 10% (Y slices) levels. The images are plotted with the same log scaling for each wavelength and angle combination. The results for N = 10⁸ are not shown as is computed relative to this case where by definition.