Rotogravure printing or just simply gravure printing is a type of intaglio printing process which uses a rotary printing press. It involves engraving an image onto a copper plated steel cylinder base.
The first step is to create a cylinder with an engraved image for each colour that makes up the design. The engraving process will create on the cylinder surface the cells that will contain the ink in order to transfer it to the substrate (film or paper). Since the amount of ink contained in the cells corresponds to different colour intensities on the substrate, the dimensions of the cells must be carefully set: deeper cells will produce more intensive colours whereas less deep cells will produce less intensive ones.
A rotogravure printing press has one printing unit for each colour, typically CMYK or cyan, magenta, yellow and key (printing terminology for black), but the number of units varies depending on what colours are required to produce the final image.