Logarithm of the effective temperature found by the FOSC as a function of the known effective temperature of the synthetic star for dwarfs when letting the minimisation be performed on the interval 0 ≤ E_B−V ≤ 1.4. The colour of the points depends on the value of E_B−V determined by the FOSC, as indicated by the colour scale on the right-hand side of the plots. The solid black line is the exact correlation and the dotted black lines show the ± 10% relative effective temperature band. Left: simulated magnitudes all have E_B−V = 0. Middle: simulated magnitudes all have E_B−V = 0.7. Right: simulated magnitudes all have E_B−V = 1.4.