HD 169142 integrated spectra measured by Spitzer (crosses), and spectrum summed from all the VISIR resolved spectra (black line, see bottom panels) are shown in the upper panel. The red curve is the sum of VISIR spatially resolved spectra from 0.0″ to 0.25″, corresponding to the inner 30 AU, and the blue curve is the sum from 0.38″ to 1.02″, corresponding to the outer disk. Correction for the flux outside of the slit is done by weighting each spectrum by the surface of a ring of corresponding radius, and width, 0.127″. Panels 2–7 show the surface brightness is measured on spatially resolved slit spectra at radii of 0″, 0.25″, … The spectra are not continuum subtracted. They probe ring-like regions of a width 0.128″ (1 pixel) and mean radii of 0″, 0.25″, … in the disk. The spectral region without data delimits the telluric ozone absorption region. The over-plotted vertical lines show the positions of the aromatic (blue) and crystalline forsterite (red) main features. The typical ±3σ error derived from background noise (50 mJy as⁻²) is shown in every panel. The grey full line shows the continuum interpolation under each band by a 2-degree polynomial.