The painting is in tempera, the ground paint being mixed with egg yolk and laid in thin glazes. The background and many details are inlaid with gold leaf and in places the panel has been tooled beneath the gilding to enhance the decorative quality. In the panel with the Virgin and Christ Child, the garments are universally blue, the pigment coming from the semi-precious stone lapis lazuli. Richard's robe uses vermilion, another expensive pigment. Some colours have faded; the roses in the angels' hair would originally have been a much deeper pink, and the green grass of the outer hart panel is now much darker than when painted.