The Enameler introduces shade both by using coloured glass or by adding pigments into the glass previous to firing. After the glass melts and flows, it cools right into a tough, smooth coating above the substrate. 'Much less is often extra,' suggests Jennifer Verruto, founder and CEO of Blythe Interiors. https://www.watchesworld.com/exploring-the-aesthetics-of-dial-design-and-decoration/