Intrinsic polarization of DH Tau B after subtracting interstellar polarization signals from the measured polarization of the companion. Top: intrinsic degree and angle of linear polarization of DH Tau B as a function of the degree of polarization due to interstellar dust, assuming an angle of 26° for the interstellar polarization. The bands around the curves show the uncertainties of our measurements. Bottom: probability distributions of the intrinsic degree of polarization of DH Tau B for a range of degrees of polarization due to interstellar dust, assuming the angle of the interstellar polarization to have the same distribution as that determined by Goodman et al. (1992) for the B216-B217 dark cloud adjacent to DH Tau. The probability distribution of each column is normalized to one.