Abstract: A mark, a method and a system for colour quality parameters measurement of a printing press. The mark comprises a plurality of spots, wherein each spot comprises encoded dot level information, the distribution of spots defines a signature pattern for each process colour, a plurality of said spots is associated to each ink key of the printing press along an area of interest and the mark is invisible to the naked eye. The colour quality parameters measurement system comprises image capturing means synchronizable with the printing press and capable of accessing the entire width of an area of interest of the printing press, processing means, user control interface for communication between the processing means and the press user and a mark according to the invention.