mostly with opaque enamel, achieving a rather different effect from medieval examples using translucent enamel. The French watchmaker Josias Jolly made frequent use of it. Technique The process for creating basse-taille enamel began by marking the outline of the design and the main internal outlines on the gold with a tool called a "tracer". Then the interior area was worked, either with chasing tools, hammering and punching rather than cutting, or with chisels, to form a shallow recess to hold the enamel. The more important parts of the design were modelled by varying the depth of the surface to produce different intensities of colour when the translucent enamel was added; for example in the Royal Gold Cup the gold under folds of drapery often rises near the surface to create a paler highlight. In the example illustrated with Luke's ox the lowest lobe shows tufts of grass formed by cutting deeper into the background. In many of the recessed areas further decoration was added by either engraving or punching which would show through the translucent enamel, or to facet the background so the reflections change as the viewing angle changes slightly. Most background areas to the enamelled scenes were decorated in the same way. Finally the surfaces were cleaned up, made good and polished, perhaps including scraping off any bumps showing through on the reverse of the metal. The enamel lies flush with the gold surfaces; it was a preparation of finely ground glass paste applied with great care to the prepared recessed areas, and then fired. When different colours of enamel meet each other with a neat boundary, this was achieved by firing one colour with a retaining border of gum tragacanth before adding the next. The difficulty was often increased by the application of tints of a different colour to a base shade of enamel before firing, so that the added colour blends gradually into the background colour around the edges of the tinted area. This is especially used on "flux", or colourless enamel, as in the ground areas, rocks and trees. In the Royal Gold Cup, flux was also used for flesh areas as on a gold background it darkens slightly when hard to a suitable colour for skin. The rouge clair or "ruby glass" red, used so effectively here, was made by adding tiny particles of copper, silver and gold to the glass; here scientific tests