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Flexography and lithography produce high-volume, reliable prints. Manufacturers use these printing techniques to produce packaging, maps, books and most other printed paper materials. Each process has its own benefits and downsides, and works best for specific purposes. While lithographic printing dominated the market for most of the 20th century, flexo printing has increased in popularity.
Modern lithographic printing uses an offset process. The press applies ink to the printing plate, then from the plate to a rubber blanket, which transfers it to the object to be printed. Most presses mount the plate and the blanket on cylinders. Flexographic printing works a little differently. It uses flexible plates mounted onto a cylinder. A partially immersed ink roller applies ink to an anilox roll, which is covered in thousands of little cups or wells that distribute ink in a uniform thickness. The anilox roll spreads the ink on the printing plate. Then, the substrate runs between the print roller and an impression cylinder. Finally, the press feeds the substrate through a dryer to prevent smudging.
Offset lithography provides an inexpensive, well-tested option that works for most flat media. Litho printing works best on flat cardboard packaging and paper. Preparing for litho printing costs little. Flexographic printing works on a wider range of substrates, including non-flat media. Unlike litho printing, flexo plates can be reused. The production process also costs much less.
Lithography production costs more, and presses can be very expensive. Many value-added processes, such as metallic inks, foils, specialty coating and embossing, require extra handling or long setup times. Flexography offers a reduced production cost, but much higher setup. It also uses more ink. Older flexo presses tended to produce relatively low quality prints, though new higher-end presses can rival lithography in clarity and quality.
Offset lithographic printing works best on flat media and in large runs. Most major book and magazine publishers use this method. Lithography also works well to produce high-quality maps and packaging where special effects or regionalization aren't priorities. Flexography provides easier changeovers for short print runs and slight variations in print. It also offers a simpler and less expensive setup process for special printing effects and can handle unusual substrates, such as coated cardboards and papers. This makes it a good choice for packaging.
G.D. Palmer is a freelance writer and illustrator living in Milwaukee, Wis. She has been producing print and Web content for various organizations since 1998 and has been freelancing full-time since 2007. Palmer holds a Bachelor of Arts degree in writing and studio art from Beloit College in Beloit, Wis.