Average deviations () versus n_z are shown for the total global SEDs and Y image slices for τ_z(1 μm) = 1 and 10 and θ = 90°. The images are for the τ_z(1 μm) = 1 and θ = 90° case and illustrate the qualitative impact of increasing n_z. The images are log scaled over the same range. The DIRTY spatial grid uses a log spacing along the z axis and this is reflected in the images shown. Only the image slices at two diagnostic infrared wavelengths probing the dust emission are shown as the ultraviolet and optical scattered light images are not sensitive to n_z for Monte Carlo codes. The dashed and dotted horizontal lines give the 1% (global SED) and 10% (Y slice) lines. The results for n_z = 200 are not shown as is computed relative to this case where by definition.