Representative line decomposition results for three of our SOFI z ∼ 2 targets. Each row refers to a different target (QBQS J051411.75-190139.4, SDSS J220245.60-024407.1, and SDSS J121843.39+153617.2), while each column refers to a different spectral region (Hβ and Hα). The observed data are shown in blue, while the cumulative best-fit spectrum is shown as an orange solid line. The different coloured lines pertain to different components in the line decomposition, as shown in the legend. Some of our targets have strong Fe II and even clear Hγ emission, as shown in the Hβ region of QBQS J051411.75-190139.4 (panel a). On the other hand, a few targets have prominent (S/N > 3) [O III] features similar to SDSS J220245.60-024407.1 (panel c). Both of these objects were observed with the GRF filter, hence other Balmer lines aside from Hα are detected. On the other hand, SDSS J121843.39+153617.2 was observed with the K_s filter (panel e). Its Hα spectrum shows a weak [N II] λ6584 feature (see Sect. 4.2).