What is Offset Printing?
Estimated reading time: 3 minutes
Offset printing is a type of printing method where ink is transferred from custom metal plates into substrates like paper or cardstock to produce prints. Offset printing is typically used in creating high-quality and image-heavy products such as magazines, brochures, catalogs, booklets, and other print products in large quantities.
3 Main Stages of Offset Printing
- Prepress Stage
This is the stage where content is designed and the layout finalized so that it’s ready for printing. As designers prepare digital files of the content, they ensure that specifications are met. This would involve verifying fonts, setting bleed marks, correcting file formats, and managing color settings to get accurate results.
It is also during the prepress stage where custom plates are made. This entails transferring the design from the digital files to the metal plates, often aluminum, using chemical processes. The types of inks that will be used for printing are also chosen at this stage. When the plates are finished, they undergo the ink and water separation treatment. This ensures that image areas of the plate attract the oil-based inks, while non-image areas (i.e., the non-printable areas) repel it with water. It is crucial that the design is final before the plate-making process begins to save time and resources. - Printing Stage
Offset printing presses are operated by individuals whose training involves calibration of ink flow from the custom plates to the blanket cylinders or rollers and finally to the paper.
When printing using the CMYK color scheme, pressers use four separate plates and blanket rollers for each color — cyan, magenta, yellow, and black — and feed the substrate to each color one at time until the design is completely printed. This process is also known as four-color printing. Meanwhile, some pressers also use the Pantone scheme, which is ideal for printing images with very specific shades and colors. - Post-Printing Stage
At the finishing stage, printed substrates undergo a drying process so that the inks are fully absorbed by the paper, thus eliminating any risk of smudging. These substrates also undergo quality control to ensure that all sheets are printed correctly and that any rejects are taken out of the pile. Printing technicians use various tools to check for color accuracy and print consistency. At times, pressers are required to create adjustments to the print job, and it’s also possible to do a reprint altogether if it’s the only way to address issues present in the batch. Approved prints are then cut, folded, and bound as needed, depending on what the final product requires.
4 Advantages of Offset Printing
- Superior Print Quality. Offset printing uses a technique called ink and oil separation, where the custom plates are treated such that certain parts such as image areas attract ink while some parts repel it. This way, the ink is transferred only to the targeted areas making the printing sharper and more precise.
- Cost-effective Printing. Offset printing is recommended for large quantity orders to maximize the custom metal plates. While creating custom plates can take time to setup, these plates can last several uses and they last a long time too, making offset printing perfect for high volume jobs like books, wrapping paper, and packaging. In addition, modern offset printing technologies allow machine operators to calibrate and control the flow of ink to minimize waste while ensuring that the right amount of ink is used to create high-quality prints every single run.
- Large Format-Friendly. Offset printing presses can handle large format substrates, which means you can produce full-sized prints, whereas digital printers are typically limited by certain paper sizes.
- Versatility With Substrates. Aside from paper stock and cardstock of various thicknesses, offset printers are able to print on other materials such as leather, fabric, and metal. If you’re creating highly specialized print products that involve different substrates, you can work with one printer to produce and assemble every component of your product.
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At UPrinting, we bring your brilliant ideas to life through exceptional printing services. With seven printing facilities across the US, each staffed by a team of seasoned printing experts using state-of-the-art printing technologies and a comprehensive 33-point print check process, UPrinting is a printing company you can definitely trust.
