Comparison of the λ = 35.11 μm edge-on images of the TRUST slab benchmark for the vertical optical depth τ(1 μm) = 10. The solutions provided by the old and new DART-Ray version are included as well as those of the other codes participating to the project. Units on the images are MJy/sr. The plots on the left show the average surface brightness profiles and the relative differences between the solutions along a vertical and a horizontal strip, whose boundaries are shown within the top two images (CRT and new DART-Ray code). The X-axis of these plots are in units of pixels. The inclusion of dust self-heating in the new version of DART-Ray allows a much closer agreement with the other codes. We note that these solutions are for the “effective grain” case (see G17).