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May

Offset and Digital Printing

The first printing presses worked by pressing ink onto a sheet of paper using raised letters and symbols. While later models featured movable type, drawings and other images had to be carved for each job. This process was costly, time-intensive, and often produced blurry and uneven images. For reference, it took Johanes Gutenberg staff around three years to finish a printing of 180 bibles.

Offset press plates work a bit differently. Instead of featuring raised edges, offset aluminum plates are processed in a way that exploit inks’ oiliness. Areas to be printed on attract oil, while non-print areas repel oil. Treated plates attach to the outside of a flat metal drum. The plate never directly touches the substrate—rather, ink is transferred from the metal drum to a rubber cylinder and finally onto the substrate. Each ink color—whether a traditional cyan, magenta, yellow, or black or a PMS spot color—requires a unique plate and an additional run through the press.

Offset presses deposit dots that work together to trick the human brain into seeing a cohesive image when viewed from a distance. You’ve probably seen this at work in magazine printings—when viewed from up close, the cyan, magenta, yellow, and black layers become distinct and you can see the individual dots. When printed correctly, a close-up of offset print appears as a series of empty-centered daisies or “rosettes.” This is where the term dpi (dots per inch) originates. The more dots, the more realistic the image appears.

The type of digital press a shop uses is often just a larger version of the inkjet or laser printers you’ve seen at home or in the office. Digital presses can handle multiple colors and variable data in the same run. High quality digital offset presses use specially coated papers and electrostatic inks. Up close, digital prints look more like a computer screen—little squares or pixels.

Traditionally, offset printing has been the standard for projects requiring the highest resolutions, such as art books, high-end catalogs, and formal invitations. Offset is also known for printing more consistently over time and working with more substrates.  If your project requires an exact color match, offset printing is more exact because it allows for spot colors. (We also recommend choosing a G7 certified print service provider. While offset presses have a higher set-up fee, they also have a lower cost-per-page, making it an economical choice for large-scale projects.

Digital print’s strength is speed and low start-up cost. Its downside is a tendency toward lower-quality images, less color consistency, and a higher cost per page. However, this gap is diminishing every day. The highest quality digital presses have only negligible differences in quality compared to offset presses and offer a competitive cost per page.

It’s great to have both kinds of printing processes as an option. If you need 50 personalized invitations printed in two days, a digital print is likely your best option.  If you need 2,000 brochures printed two weeks from now, offset is likely your best option.

Want to know more about the differences between offset and digital printing? Talk to your local print provider to discuss the best option for your unique needs.

- Sarah Barker, ,

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