The method of commercial printing which involves the photographic transfer of an image to a metal or plastic plate that is wetted with water. The image section of the plate picks up oil based ink from the roller while repelling the ink. Whereas, the non image section repels the ink while retaining the water. The image is then transferred to rubber or plastic sheet and from there it is printed on the paper. The double transference makes sure of a smooth finish as the rubber sheet is relatively smoother compared to the printing plate .