Examples of intensity determination for overlapping or nearby lines, in H II template spectrum. The x-axis has been shifted so that the zero point matches the wavelength in µm displayed in the top left corner of each panel. Blue curve: Fitted model consisting of a linear continuum and two or three Gaussian profiles. Dotted lines: central wavelengths of the Gaussian profiles. Upper left panel: [Ni II] 6.636 µm and H I 6.638 µm. Lower left panel: complex of three H I lines, with fitted wavelengths at 7.4955, 7.5030, and 7.5086 µm. Right panel: H I 5–6 and contributions by He I multiplets in its left wing.