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Publication of BE715499ApublicationCriticalpatent/BE715499A/xx
B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
B41M5/00—Duplicating or marking methods; Sheet materials for use therein
B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
B41M5/30—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers
B41M5/32—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers one component being a heavy metal compound, e.g. lead or iron