COLOUR LASER MARKING OF ARTICLES AND SECURITY DOCUMENTS PRECURSORS

摘要

A method of color laser marking an article having a polymeric foil with at least one colorless layer containing an infrared absorber, a polymeric binder and a color forming compound; including the steps of:—laser marking the colorless layer with an infrared laser using a first laser operation mode to generate a blue or cyan color; and—laser marking the same colorless layer with an infrared laser using a second laser operation mode to generate a black color, wherein the first laser operation mode applies less energy to the colorless layer than the second laser operation mode. Also disclosed is an article, such as a security document, including a polymeric foil and a colorless layer containing laser marked graphical data having a blue or cyan color and laser marked information having a black color.