Half shade polarimeter is very sensitive for those persons who are suffering from colour blindness. It is only suitable for a particular wavelength since the quartz half will work as a half wave plate for a particular wavelength.
In contrary to it biquartz polarimeter is more accurate than half shade polarimeter and equally works with white light.
A person suffering from colour blindness can not work with biquartz polarimeter. It is difficult to adjust the analyzer in a position for which the tint in both the halves is same.