Process for decorating watch components

A process of decorating a watch component (1) with a white coating comprising the following steps:

• preparing the watch component (1) and installing said component in a deposition enclosure;
• depositing a metal adhesion layer (10) over the entire watch component by physical vapor deposition;
• depositing a diffusing layer (12) of aluminum over the entire component, under a flow of reactive gas, the rate of reactive gas is maintained so as to obtain a layer of aluminum doped with 0.5 atom % to 10 atom % reactive gas, so that the aluminum layer crystallizes in the form of a faceted crystalline structure, via physical vapor deposition;
• reducing or cutting off the flow of reactive gas when the diffusing layer has reached the desired thickness in order to terminate the diffusing layer (12) with a thin layer of pure aluminum (13);
• and
• depositing a transparent protective layer (14) by atomic thin-film deposition.