Silicate extraction procedure in the Elias 29 spectrum. Top: black line shows the optical depth scale of the Elias 29 spectrum calculated in this paper. Red and blue lines show, respectively, the scaled CGS 3 and synthetic silicate bands at 9.7 μm and 18 μm. Bottom: red and blues lines show the Elias 29 mid-IR optical depth after silicate band extractions with scaled CGS 3 and synthetic silicate profiles, respectively.