Applied indices are hour markers physically fixed to the dial surface, distinguished by construction and rendering from printed or painted ones. The difference is not merely aesthetic: an applied index has actual thickness, casts its own shadow, and responds to light in ways no printing can replicate.
Fastening technique varies. The most common methods are adhesive bonding with industrial glue and riveting through tabs passing through the dial, called pieds. This latter system guarantees superior mechanical retention and is preferred in refined segments, where vibration from automatic movements over time can compromise adhesives. In high-pressure dive watches, like certain Seiko Prospex models, indices are sometimes soldered to eliminate any risk of detachment at depth.
Form matters as much as method. Stick indices are most widespread: a rectangular bar in polished or satin metal. Yet even within this simple shape significant variations exist. Some examples, like certain Jack Mason watches, feature brushed tops and inclined polished edges: the beveled portions point toward the dial center and capture light toward the wearer's eye. Faceted indices multiply this effect across multiple planes, creating depth through geometry alone.
Semi-flying indices, which I know less from personal experience, would be applied on a plane raised above the dial, achieving a floating effect. I've seen them described but haven't disassembled enough to speak with the same confidence.
The three-dimensionality of applied indices interacts with the underlying dial type. On a sunburst background, metallic relief captures different reflections depending on angle; on a guilloché background it creates planar contrast that enhances both finishes. On a tuxedo dial, where center and outer ring have different textures, applied indices along the inner bezel serve as a formal transitional element.
Filling with photoluminescent material, usually Super-LumiNova, is compatible with applied indices: the internal cavity of the index is filled during production. The amount of lume depends on the index's internal volume, so models with more substantial indices tend to have greater luminous reserve compared to flat-printed indices.