Gillie Hoyte Byrom
Gillie makes enamel portrait miniatures to commission. Each painting is a multi-layered sequence of onglaze pigment, sometimes with decoration. She also teach these specific skills and has self-published a book 'The Practice of Painting in Enamel' which describes how to apply and successfully fire fine layers of enamel - available on her website.
Head over to Gillie’s website.