BASICS: The image carrier in the gravure process is generally a steel cylinder with a copper-plated surface in which small recesses, called 'cells', are made which carry the ink. The surface is normally then plated with hard chromium to improve its wearing properties.
In the press, there is a printing unit for each cylinder. The surface of the rotating cylinder dips into an ink pan which fills the cells with ink (the inks for gravure printing are very fluid, whereas offset litho ink is paste-like). Surplus ink is then wiped off the cylinder surface by the squeegee action of the doctor blade, leaving ink only in the cells. The impression roller then presses the paper web onto the cylinder, and the ink transfers onto the paper.
Gravure applies the ink in controlled doses from different sizes of cell. The larger the volume of the printing cells, the more ink is transferred and the stronger the tone which is reproduced by them.