Sequences of colour–magnitude positions assuming a steady accretion disc and, for each panel, a given value of the white dwarf dipole moment (μ₃₀ = μ/10³⁰ G cm³). Each sequence is obtained by varying Ṁ up to 10¹⁸ g s⁻¹ for a given P_orb. The orbital period increases from the bottom left sequence (P_orb = 80 min) to the top right sequence (P_orb = 7 h). The thin grey lines trace only the contribution of the disc. The dashed lines add light from the companion star, the white dwarf, and the bright spot. The stars indicate the location of the combined light from the companion and white dwarf for each P_orb sequence. The square indicates the position of the most luminous bright spot emission. When μ₃₀ ≠ 0, the inner disc is truncated at the magnetospheric radius R_m. The thick red and blue lines overplotted on the dashed lines highlight the location of hot and cold stable steady discs, respectively. The green rectangles delimit the upper and lower hook regions defined in Fig. 2.