Perlage is a decoration of small overlapping circles. It belongs to the vocabulary of watch finishing, but its presence alone is not a certification. To recognise and describe it precisely, distinguish the pattern, the decorated surfaces and the limits of observation. The Fondation Haute Horlogerie and A. Lange & Söhne provide the explicit references used here.
Small overlapping circles
The Fondation Haute Horlogerie defines perlage, also called œil-de-perdrix, as small circles that partially overlap. It describes using a flat-ended wooden peg rotated against a bridge or plate surface. This documents one technique, without prescribing universal tooling for every manufacture.
A. Lange & Söhne describes decoration produced with a rotating abrasive tool. Both descriptions support its circular character and production with a rotating tool. No speed, pressure or grit size is specified here: the cited sources do not establish those parameters.
Where can perlage be seen?
A. Lange & Söhne states that it applies perlage to inner surfaces of plates and bridges and to the dial side of the main plate, invisible in the assembled watch. These are practices documented by that manufacture, not mandatory locations for all watches.
Distinguish what a transparent caseback reveals from what remains hidden. No visible perlage does not prove that inner surfaces are undecorated. Conversely, a visible decorated surface does not establish the treatment of every movement area. Do not dismantle a watch simply to look for a pattern.
Perlage, stripes and anglage: different finishes
Perlage appears as a sequence of partially overlapping circles. Geneva stripes form bands; anglage concerns edges. These are different treatments, not three names for a shiny movement.
The Fondation Haute Horlogerie describes several decoration and finishing techniques. TIMELAB also distinguishes surfaces, flanks and chamfers in its bridge and plate criteria. When describing a component, link each term to a specific area.
Observe without attributing unproven functions
In a clear photograph, look at circle shapes, overlap and the limits of the decorated surface. Change viewing angle when examining an actual watch. These steps help read the pattern; they do not measure timekeeping accuracy or certify the movement.
We attribute neither dust trapping nor a quantified performance improvement to perlage: the cited documents do not establish those claims. Nor do we infer entirely manual execution from appearance alone. Ask for manufacturer documentation to learn the process used for a particular reference.
A useful approach for students and collectors
Students benefit from identifying plates, bridges and edges before naming their finishes. Collectors can then separate aesthetic preferences from technical specifications and available evidence. Decoration is a precise subject of observation, not an answer to every question about a watch.
Our article on the Geneva Seal distinguishes decoration from certification. The guide to starting a collection complements this approach; the Décalibre School introduces movement components.
Frequently asked questions
What is perlage in a movement?
A decoration of small overlapping circles applied to movement component surfaces.
Is it always visible through the caseback?
No. Lange documents applications on inner surfaces and the dial side of the plate, invisible in the assembled watch.
Does perlage guarantee accuracy?
The cited sources describe decoration. They do not establish that it alone guarantees timekeeping performance.
Sources
Fondation Haute Horlogerie: definition and tool example. A. Lange & Söhne: rotating abrasive tool and locations at Lange. Fondation Haute Horlogerie and TIMELAB: distinction between surface and edge treatments.