Joseph Sullivan, an artist based in England, uses a variant of a 15th century Flemish method of painting - since termed the mischtechnik - in which egg tempera is used in conjunction with oil and resin glazes to allow both subtle gradation of colour and fine detail, with a concomitant luminosity produced by light reflecting through the layers of various coloured glazes. In addition to these works, sketches are occasionally made in oil on panel, and works on paper in tempera.