Challenges for Coated Papers and Paperboards on 4-Colour Plus Printing Machine

4-Colour printing has been around for many years and today most of the printing companies have 4-colour printing machines, a few have 5- and 6-colour printing machines, and far fewer companies have 8-colour printing machines installed. 8-colour printing machines have 8 printing units and, therefore, the papers and paperboards on such machines have far more stress compared to 4-colour printing machines. On litho-offset printing machines we use ink as well as water (dampening solution) on each of the printing unit that affects dimensional stability of papers due to hygroscopic characteristics. The objective of the experiment is to study the printability and behaviour of papers and paperboards of 4-process colour printing on 8-colour printing machines as opposed to 4- and 6-colour printing machines, and correlate the print results with laboratory print evaluation. Laboratory analysis of coated surface and printed surface is presented of 4-process colour printing on 4-, 6- and 8-colour prints on papers and paperboards as well as 4 over 4 colours on papers. Comparison between imported and Indian papers and paperboards is also presented.