thumb|Diagram of rotogravure process

Rotogravure (or gravure for short) is a type of intaglio printing process, which involves engraving the image onto an image carrier. In gravure printing, the image is engraved onto a cylinder because, like offset printing and flexography, it uses a rotary printing press.

Once a staple of newspaper photo features, the rotogravure process is still used for commercial printing of magazines, postcards, and corrugated (cardboard) and other product packaging.

History and development

In the 19th century, a number of developments in photography allowed the production of photo-mechanical printing plates. Henry Fox Talbot mentions in 1852 the use of a textile in the photographic process to create half-tones in the printing plate. A French patent in 1860 describes a reel-fed gravure press. In 1906 they marketed the first multi-colour gravure print.

Features

Because gravure is capable of transferring more ink to the paper than most other printing processes, it is noted for its remarkable density range (light to shadow) and hence is a process of choice for fine art and photography reproduction, though not typically as clean an image as that of offset lithography. A shortcoming of gravure is that all images, including type and "solids," are actually printed as dots, and unless the ink and substrate combination is set up to allow solid areas to flow together, the screen pattern of these dots can be visible to the naked eye.

Gravure is an industrial printing process capable of consistent high quality printing. Since the Gravure printing process requires the creation of one cylinder for each colour of the final image, it is expensive for short runs and best suited for high volume printing. Typical uses include long-run magazines in excess of 1 million copies, mail order catalogs, consumer packaging, Sunday newspaper ad inserts, wallpaper and laminates for furniture where quality and consistency are desired. Another application area of gravure printing is in the flexible-packaging sector. A wide range of substrates such as polyethylene, polypropylene, polyester, BOPP, etc. can be printed in the gravure press. Gravure printing is one of the common processes used in the converting industry. High initial setup costs and extended lead times contributed to rotogravure's general failure in the publication printing sector, yet the method remains dominant for flexible packaging in Asia (where it holds an estimated 80% market share) and maintains a strong presence in Europe, in contrast to its stagnation in the Americas.

Rotogravure presses for publication run at per second and more, with paper reel widths of over , enabling an eight-unit press to print about seven million four-color pages per hour.

The vast majority of gravure presses print on rolls (also known as webs) of paper or other substrates, rather than sheets. (Sheetfed gravure is a small, specialty market.) Rotary gravure presses are the fastest and widest presses in operation, printing everything from narrow labels to 12-foot-wide (3.66-meter-wide) rolls of vinyl flooring. For maximum efficiency, gravure presses operate at high speeds producing large diameter, wide rolls. These are then cut or slit down to the finished roll size on a slitting machine or slitter rewinder. Additional operations may be in line with a gravure press, such as saddle stitching facilities for magazine or brochure work.

Advantages

Although the rotogravure printing process is not the most popular printing process used in flexible-packaging manufacturing, it does have the ability to print on thin film such as polyester, polypropylene, nylon, and polyethylene, which come in a wide range of thicknesses, commonly 10 to 30 micrometers.

Other appreciated features include:

  • printing cylinders that can last through large-volume runs without the image degrading
  • good quality image reproduction
  • low per-unit costs running high volume production

Disadvantages

Shortcomings of the gravure printing process include:

  • high start-up costs: hundreds of thousands of copies needed to make it profitable
  • rasterized lines and texts
  • long lead time for cylinder preparation, which is offsite as the techniques used are so specialized
  • rotogravure cylinder manufacturing utilizes hexavalent chromium electroplating. OSHA states that "all hexavalent chromium compounds are considered carcinogenic to workers."

See also

  • Flexography
  • Offset printing
  • Photogravure
  • Roll slitting
  • Rotary printing press

Notes

  • European Rotogravure Association
  • Gravure Association of the Americas
  • Heliograph holding
  • Print Reviews