  Heavy metal subdwarfs are a class of hot subdwarfs with very high abundances
of heavy elements, typically around 10 000 times solar. They include stars
which are strongly enhanced in either lead or zirconium, as well as other
elements. Vertical stratification of the enhanced elements, where the element
is concentrated in a thin layer of the atmosphere, has been proposed as a
mechanism to explain the apparent high abundances. This paper explores the
effects of the vertical stratification of lead on theoretical spectra of hot
subdwarfs. The concentration of lead in different regions of the model
atmosphere is found to affect individual lines in a broadly
wavelength-dependent manner, with the potential for lines to display modified
profiles depending on the location of lead enhancement in the atmosphere. This
wavelength dependence highlights the importance of observations in both the
optical and the UV for determining whether stratification is present in real
stars.
