Laser annealing is used with all metals which show a color change when exposed to heat and oxygen. The laser marker selectively heats up small spots of the workpiece surface until annealing colors appear. Annealing leaves the material surface unharmed but still produces high-contrast, clearly legible markings.

Usually the laser marker engraves the material surface down to some 10 µm in depth. Engraved marks are exceptionally durable and can only be removed by heavy grinding. Therefore laser engraving is used for forgery-proof product marking.

Selective ablation of lacquer coats or anodizing layers shows a different-colored material underneath and produces colored markings.