What’s Behind Black?
Being seen without us knowing where it comes from: such is the dark destiny of black, watchmaking’s lucky color. Let’s find out more by taking a walk on the dark side!
Behind each color lies a pigment and/or a material. Black is no exception – but contrary to the hues found in enameling, for instance, achieving this particular color calls for highly technical (and indeed technological) processes.
PVD, DLC, and ADLC: Spot The Difference
Watchmaking usually uses two techniques to turn cases (traditionally made from grey steel) black. The first is Physical Vapour Deposition (PVD). This is a surface treatment involving vacuum deposition, in which multiple black layers are applied to the surface of raw material. In theory, the coating can become scratched, but in practice, the number of coats applied makes it highly resistant.
DLC (Diamond-like carbon) is also applied in a series of thin layers in a vacuum, but is far more resistant, scoring between 1000HV and 5000HV in a Vickers hardness test. By comparison, the hardest naturally found material, diamond, has a Vickers number of only just over 100HV.
A very similar acronym is ADLC, also referred to as DiamondBlack, a registered trademark belonging to Ionbond. The gaseous process and the relatively low coating temperature of < 200 °C involved are ideal for the coating of complex shapes and delicate materials for which the traditional PVD process cannot be used. The coating thickness of just 2-3µm allows the original polished or matt structure to be preserved, without the need for post-treatment.
And Then There Was Carbon…
Surface treatments aside, certain materials are naturally black already. Carbon is one of them, with some grey highlights. Countless brands have used it, but some pieces stand out in particular; one is the TAG Heuer’s highly atypical creation for Only Watch, a carbon reinterpretation of its iconic and extremely rare ‘Dark Lord’ Monaco that combines an avant-garde design and cutting-edge materials – most notably a carbon hairspring, one of TAG Heuer’s specialties.
At The Heart of The Matter
Historically, however, black has run up against its limits when it comes to materials. Black ceramic, for instance, is more difficult to produce. In its original state, the organic compound in question is a milky powder, for which through-coloring aimed at producing a dark, uniform black is a highly complex operation.
However, the Swatch Group now has its own ceramics unit, Comadur. This has developed Zircon, a high-tech ceramic that has opened up two new areas of potential: color and finish. As a result, it’s now possible to find perfectly-produced black ceramics, coupled with polished or matte finishes – moreover, these are deemed to be age-resistant due to their hardness.
Following this innovation, Rado has developed a large number of black ceramic models. The brand’s approach is noteworthy for two reasons: firstly, because it has made black ceramics more widely available, and secondly because it has also extended the use of this color to women’s watches – just as Chanel, the pioneer of black in women’s watches did with its J12 in 2000. Black ceramic has also been used by Chanel in its Monsieur collection, and extensively by Hublot.
Among the independents, H. Moser & Cie. has made widespread use of Vantablack, a black material that absorbs 99.965% of visible light. Since the eye requires reflected light to see objects, Vantablack is perceived as an absence of material – a black hole in the making.