uurlijnen

Uurlijnen are lines on a time-telling dial that indicate the hours of the day. In Dutch, the term combines uur (hour) and lijn (line) and is used to describe the markings that help a user read the current time on clocks, watches, and related devices.

On analog clocks and wristwatches, uurlijnen form the hour markers around the edge of the dial. They are usually arranged in a circular pattern, with twelve main lines corresponding to the hours and additional shorter marks for half- and quarter-hours. In many designs, the uurlijnen are accompanied by numerals or simple indices, and they may be rendered in various styles, from minimal to highly decorative. Modern watches may also apply luminescent material to the hour lines to improve visibility in low light.

Uurlijnen also appear on sundials, where they serve a different purpose. On a sundial, lines are not evenly spaced because the sun’s apparent motion is not linear relative to the Earth’s rotation. Hour lines are calculated for a specific latitude and often take the form of curved or irregular patterns on the dial plate. The gnomon, which casts the shadow, must be aligned with the Earth's axis, and the intersection of the shadow with the hour lines indicates local solar time.

Historically, uurlijnen have been essential for timekeeping before and alongside mechanical clock faces. They reflect both practical considerations of time division and stylistic choices in clockmaking. Today, they remain a fundamental element of traditional timepieces and decorative horology.