Methods for laser marking color precursors security document

Method for marking by color laser precursor security document comprising at least: - a polymer sheet, and - at least one forming layer colorless color to generate a color different from black containing at least one absorber of infrared light, color forming compound and a polymeric binder, and - a markable polymeric support by laser selected from the group consisting of polycarbonate, polyvinyl chloride, polystyrene-acrilonitrolo-butadiene and copolymers thereof or markable layer by laser including a laser additive and a polymer selected from the group consisting of polystyrene, polycarbonate and acrylonitrile polystyrene to produce a black color, said method comprising the steps of: - marking laser forming layer colorless color by an infrared laser used in pulsed mode at a frequency pulse repetition of at least 15 kHz to generate a color different from black, and - dialing l be the markable polymeric support laser markable layer or the laser by the same infrared laser used in pulsed mode at a repetition frequency 5 kHz maximum pulse to generate a black color.