Illustration of the residual spectra obtained by subtracting theoretical spectra scaled by the fractional contribution from the HR06 OB2 data in the vicinity of He I 4471 Å line. The value of log g increases in steps if 0.25 dex from log g = 3.00 dex for the lower curve to 4.25 dex for the uppermost curve, spectra are offset by 0.2 normalized flux units. T_eff values follow the relationship shown in Fig. 5. The emission feature at the position of the He I line core (dashed line), caused by over-subtraction of the Doppler core in the model, becomes weak or absent for log g > 3.75.