ROTARY PRINTING

LITHOGRAPHY

This can be sheet fed or on a roll. It prints 'positive-reverse-positive'. The design/images get broken down and then printed. The substrates that are used tend to be paper based, such as news prints, magazines, anything thats largely flexible.

'WEB OFFSET MACHINE'

This is a much larger form of lithography, they use huge rolls, its a high speed production. This is roll fed opposed to sheet fed.

ROTOGRAVURE

This is a more refined process of printing. They use copper plates set between 2 rollers. This works on a reverse image basis. It's very expensive but because of the copper plates they last longer. Larger runs tend to use this technique, and if they are printing on a tough substrate. It has a really dense ink coverage, and its a deeper etch.

Floor coverings tend to use rotogravure, also some magazines use this technique. I was curious whether you had to change the plates every time you had a new magazine for example, as there would be new images and text. It turns out you would have to, this can prove to be extremely expensive.

The accuracy with this print technique is very good.

FLEXOGRAPHY

This is made from a rubber polymer on a cylinder. It uses a positive mirror image. The only problem with this technique is that the registration isn't as accurate. They use the CMYK process, the image is raised about 2-4mm. The tend to print on bottles, plastic substrate, cartons, food bags such as kit kat bags or minstrel bags.

Aluminum cans, they tend to be printed on a flat surface and then its rolled around the can.