After finalising the colours we’d launch with we used a small vial of blue that’d been sitting in the studio for several years. It was a transparent enamel rather than an opaque, and it’d been mixed up and used by accident. Transparent enamels don’t work on copper as the metal blackens with the heat and that comes through making the dial dark and muddy. We’d experimented with them early on, with some success on precious metals, but had then focused on opaques.
This blue is an exception to that, the depth of colour was unlike anything else we'd seen. We changed the line-up and swapped it in.