Observed (grey dots) and corrected for completeness (black dots) I_E-band LF derived excluding the three cD galaxies NGC 1275, NGC 1272, and NGC 1265. The solid red and blue lines and the associated dotted lines show the best-fit and 1 σ confidence regions of the Schechter and Schechter + Gaussian LF parametrisations, respectively. The vertical grey dashed line shows the 50% completeness limit. The two LFs are compared to those available in the literature for the Perseus cluster in the K band (Meusinger et al. 2020), in the r band (Aguerri et al. 2020), and in the B band (Penny & Conselice 2008), to the mean i-band LF of SDSS local clusters derived by Popesso et al. (2005) within 0.5 h⁻¹ Mpc from the cluster centre, and to the Cluster-EAGLE simulations (Negri et al. 2022). The LFs of Perseus have been derived on different fractions of the cluster. They have been shifted to the I_E band using the mean colour of galaxies in the cluster, and in the Y-axis direction to visually match the data. The best fit parameters are given in Table 3.