What characterizes a retrograde hand in watchmaking?

A retrograde hand in watchmaking is characterized by its movement along an arc before it returns to its initial position. This unique function allows the hand to traverse a set range, such as indicating minutes or seconds on a curved scale, and once it reaches the end of that range, it snaps back to the starting point. This type of hand movement adds an interesting visual dynamic to timekeeping, distinguishing it from other types of hands that may continuously rotate or function in a linear manner. Retrograde mechanisms are often appreciated for their artistry and technical complexity, making them a sought-after feature in luxury watches.

The other options describe different types of hand movements not associated with the retrograde mechanism. For example, movement in a straight line or continuous rotation represent more conventional hand functions found in standard watch designs, while a digital format does not pertain to traditional analog watches where retrograde hands are typically utilized.