The observed colour-magnitude (top panels) and colour–colour (bottom panel) diagrams of PSR J1357−6429 field stars. The counterpart candidate labelled by C is shown by red, and nearby stars marked in Fig. 2 are shown by black. Empirical main-sequence colour–colour curves reddened with a zero, medium, and entire Galactic extinction, A_V = 0,2.0, and 5.9, are shown at the bottom panel by green, red and yellow lines, respectively. The spectral classes are marked by filled squares and indicated along the green curve. The extinction vectors in the bottom panel show where C-object should move after dereddening with A_V = 2.0 or 5.9.