Flexography is a rotary relief printing process in which ink is applied to the raised surface of an image on a flexible printing plate and, from there, to the surface of a label or flexible packaging substrate. The key differences between letterpress printing (which also uses a relief printing plate) and flexographic printing lie in the printing plate and the method of metering and applying the ink to the surface. Printing plates for flexographic printing may be made from a softer, more resilient rubber or flexible photopolymer plate material than letterpress, though similar exposure and wash out stages to that of letterpress are required.

Rather than the thicker, sticky ink used for letterpress printing, the flexographic process uses a very thin solvent or water based ink. The thin ink requires a special type of ink metering system, which uses an engraved anilox roll containing thousands of tiny recessed cells – which carry the ink - and a doctor blade which removes the excess ink from the anilox roll surface. The degree of fineness and the shape of the cells can be changed depending on the effect required.

Narrow web flexographic printing is the most widely used label printing process worldwide for the production of self adhesive labels. Apart from narrow web, flexographic presses are also used for mid and wider formats as well as sleeves, wrap around film labels and the printing of flexible packaging and cartons.