Hand guilloché is an artisanal technique, one which few manufactures have mastered so completely, in which the material is engraved to produce a repeating decorative pattern. The concentric pattern on the dial of the Toric Hémisphères Rétrograde Slate evokes the arrangement of the scales on a pine cone – one of the innumerable examples of the Golden Ratio seen in the natural world.
The knurled bezel is a distinctive feature of the Toric timepiece. To create this component, which is so crucial to the iconic design of this model, Michel Parmigiani took his inspiration from the structure of a Doric column. Knurling is a technique which consists of manipulating the material by hand, using a wheel that leaves the imprint of its notches in the metal. This means each timepiece is unique. The knurling is created by a craftsman at the watchmaking centre, who has added this touch to every Toric since 1996.
The Toric Hémisphères Rétrograde Slate has two independent time zone indicators, each accurate to the nearest minute. The crown at two oclock is used to independently adjust the module controlling the second time zone indicator. Once the settings are complete and the crown is pressed in, the module is coupled to the movement again, and the two time zones are synchronised. Two day/night windows show the time of day for each time zone.
The self-winding calibre PF317 shows two time zone indicators which can be independently adjusted to the nearest minute. Each time is associated with a day/night display. It also features an instant retrograde calendar which is indicated by the third central hand. Its two series-coupled barrels ensure excellent rate regularity and a power reserve of 50 hours. Its balance oscillates at a frequency of 28,000 vibrations per hour.
