Girard Perregaux Tip of the Week #43

To protect the mechanism, watch cases are nowadays moisture-proof and dust-proof.

Previously, the exterior components did not provide this water resistance, which was one of the reasons why watchmakers decorated the various components of the movement. The screws and other steel parts, for example, were polished rather then matte, to ensure greater corrosion resistance. Brass parts, such as the main plate, were adorned with Cotes de Geneve to capture dust and prevent it from penetrating into the train wheels and disrupting the workings of the mechanism. Besides their aesthetic enhancements, watchmaking decorations and finishes had a mechanical utility.