Gravure Printing Finds a High-End Home on Pouches

At this point in time industry producers agree that gravure, with its capability of printing long runs of 175-line screen images and vibrant colors consistently and in tight register, is the dominant process for printing pouches. However, flexography continues to achieve new quality levels and will continue as a competitive technology.

Gravure is a printing method that typically uses engraved cylinders as the image carriers as opposed to plates used in offset printing. Although it is a direct printing method (unlike flex and letterpress which print directly to substrate from raised surfaces), gravure images are etched into the surface of the metal cylinder as a collection of tiny cells. The cylinder rotates in an ink fountain and ink collects in the cells. Excess ink is scraped from the non-image areas by a doctor blade.

The plastic film or paper passes between the gravure cylinder and a rubber-coated impression roller, and ink is transferred by a combination of capillary action and the pressing of the substrate into the engraved cells of the cylinder, helped by the rubber surface of the impression roller. Most gravure printing today is web-fed rotogravure printing and is used both for high-end packaging applications and high-end, very long run publication printing.

Package designers who are not familiar with the process can get up to speed by talking to their printers. Cylinders are a significant cost element in a gravure job and good design can avoid unnecessary expense in this area. For instance, Dean Hoss at Pyramid recalls a client roll out of a beef jerky product in five different flavors. As originally designed, the project would have required 49 cylinders. Pyramid was able to design the job so that only 16 cylinders were required.