How did Renaissance painted enamel artists imitate oil paintings?

During the Renaissance, enamel artists sought to emulate the aesthetic and depth of oil painting by utilizing metal sheets as their canvas and vitreous enamels in place of traditional oil paints.1

To achieve this, they employed several sophisticated techniques:

• Grisaille: This method involved painting with pulverized white enamel on a dark (usually black or blue) enamel ground. By applying the white pigment thickly in light areas and thinly in darker areas—allowing the dark background to show through—artists created dramatic contrasts of light and shade, resulting in a pronounced sense of three-dimensionality and low relief.23
• Subtle Modeling: To enhance the realism of grisaille scenes, artists often used a needle or pointed tool to hatch the enamel, revealing the dark ground beneath for finer detail.3
• Layering and Finishing: In colored painted enamels, artists would apply transparent enamel colors over the grisaille treatment. They often heightened these works with thin, hatch-like lines of gold or by placing transparent enamels over metallic foil to increase brilliance.3

These methods allowed Renaissance enamellers to produce works that captured the artistic ambition of contemporary painters, despite the medium's inherent size limitations.1