The Identification of Colour Photocopiers: A Case Study

This paper reports the discovery of dotted patterns on photocopies of Hong Kong $500 banknotes seized in a clandestine workshop and the utilization of the matrix of dots for the identification the Rank Xerox colour photocopying machine used for counterfeiting the banknotes. A survey on various models of colour photocopies of the Canon and Ricoh brands resulted in the observation of dotted motifs on photocopies from the high-ended models of the Canon copiers. These dotted motifs are probably also identification marks.