Mid-infrared (5–25 μm) spectrum of NGC 6120, observed with the IRS spectrograph aboard Spitzer, representing a typical star-forming galaxy (BPT class). In this spectrum, we mark the wavelength coverage of our four custom photometric bands, labeled in Table 2. The first three photometric bands (PAH1, PAH2, and PAH3) cover the strongest PAH emission features, while the last band (Cont215) covers a continuum region of the spectrum.