Shortly after 1700, vellum (animal skin) gave way to slices of ivory as the preferred medium for portrait miniatures. Ivory provided a luminous sheen behind translucent watercolors, but the material had a problematic oily and non-absorbent surface. It took decades for artists to refine their established miniature painting techniques.
Bernard Lens III was the first British artist to paint on ivory. He adopted a stippling technique to help the watercolor pool onto the unforgiving slippery surface.