Illustration of the aperture-correction flow for the case of the Hδ_A + Hγ_A index at z = 0.1. In panels a–g the filled circles represent CALIFA simulated spectra, color-coded by the difference Δ(Hδ_A+Hγ_A) according to the color bar. The gray contours overlaid in each panel are the isodensity contours (enclosing 0.05, 0.20, 0.50, 0.75, 0.95, 0.99 of the sample) for SDSS galaxies with S/N ≥ 10 at z = 0.1 ± 0.005. Panels a–c and g display the points in the fiber-index vs. color plane, while panels d–f are in the effective radius vs. absolute magnitude plane. (a) Original difference between the index measured in the full integrated spectrum and the one in the fiber spectrum. (b) Amplitude of the first-order correction. (c) Residual difference between the index from the integrated-flux and the fiber value corrected at the first order. (d) Same as c, but in the effective radius vs. absolute magnitude plane. (e) Second-order corrections. (f) Residual difference between the index from the integrated-flux and the fiber value corrected using both the first-order and the second-order corrections. (g) Same as f, but in the fiber-index vs. color plane. The histograms in panel h display the following distributions: in filled green the original differences between integrated and fiber values (points in panel a); in dashed red the differences between integrated and fiber values corrected at the first order (points in panels c, d); in solid blue the differences between integrated and fiber values corrected at the second order (points in panels f and g). The vertical arrows on the top axis indicate the median (long arrow) and the 16th and 84th percentiles (short arrows) of the distributions of the corresponding color.