Kreisler dials are produced using two distinct methods: acid-etched German silver and Grand Feu (big fire) enamel, each drawing from a different tradition.
Acid etching is a subtractive technique with roots in early industrial craft. Select areas of the dial are exposed to acid that gradually removes material and leaves behind a design in relief. The process of etching metal with acid has been known since the 1400s, often used to create intricate designs in suits of armor. By the 19th century, it was widely used in toolmaking and instrument production.
German silver is chosen for its stability and fine grain. Despite the name and silvery appearance, it is a copper based alloy and contains no silver at all. Still it has long been used in watches and precision instruments for its resistance to corrosion and its ability to hold sharp detail in relief. Added benefit is its ornamental surface that doesn’t reflect light in a way that could harm visibility.
Grand feu or vitreous enamel has been used in decorative arts for thousands of years and is valued for its permanence. Its lustrous depth of color is unmatched by modern materials and it does not fade, patinate, or degrade in normal use.
Finely ground glass powder is applied by hand to a metal base and fired in a kiln at temperatures exceeding 700°C. The technique earns its name as the powder often bursts into flames before it liquifies, and fuses to the metal base. Any defect; cracking, bubbling, or distortion renders the dial unusable. Enamel dials were common until the mid 20th century when less volatile coloring methods were popularized.