Printing processes have come a long way since Johannes Gutenberg’s invention of the printing press in 1440. Today, the most popular printing methods for commercial projects are offset printing and digital printing. Throughout the 20th century and for much of the early 2000s, the offset printing press was often the only and certainly the best source of quality printing. But technological advances sought to develop printing processes less expensive than offset printing, with a faster turnaround and less damaging to the environment.
As more individuals wanted to print their own projects new technologies, inks, and printing surfaces came online. So, what is offset printing, and how does it compare to newer technologies like digital and UV printing?
Offset lithography, or offset printing, as it is more commonly known, was invented in 1875 and continues to be widely used today. An offset printing press uses etched metal plates that are created for each project or project portion. To offset print full-color projects, the process requires a separate metal plate for each of the four primary ink colors: cyan, magenta, yellow, and black. If both sides of the page are to be printed, you’ll need four plates per side. Every metal plate is laser etched with the image and text to be printed, as well as the negative space around each image and letter.
Next, each plate is carefully treated, with the parts to be printed made ink-receptive and water-repellant, and the negative space made to absorb water and repel ink. Each plate is then loaded with liquid ink and water. The water repels the ink, and vice versa, thereby keeping the negative space of each image ink-free. This process ensures script, clean lines, text, and images.
Now, the metal plates transfer the image to a rubber “blanket” that is used to roll the image onto paper. Once each page is printed, it must be given ample time to dry, or it will become smudged. Because the printing plates transfer the ink to the rubber blanket and not directly onto the printed surface, it is called offset printing. Printing newspapers is the quintessential use for offset printing.
As you can see, offset printing is labor-intensive and requires significant expertise to set up. However, once the setup is accomplished, offset printing is highly efficient and delivers exceptional results. While far too expensive for small print runs, offset printing is still widely used for larger print runs of 5,000 pieces or more.
Digital printing was introduced in 1989, taking advantage of the newly developed computers. Unlike offset printing, digital printing required no metal plates or rubber blankets. Instead, a digital-based image is printed directly onto a variety of papers or card stocks. Initially, the quality lagged far behind that of offset printing.
Rather than using the four-color process, digital printing uses three colors, red, green, and blue (RGB). The resulting color prints are not as exact a color match as provided by offset printing. And digital printing output was largely restricted in size. But digital printing led to a revolution!
Digital printing ushered in the age of desktop publishing, putting the power to design and produce attractive, professional-looking flyers, reports, and cards into the hands and homes of individuals. While the quality was not as high, digital printing was fast and well suited to print lots of single sheets and small batches impossible with offset printing.
The value of digital printing was clear, but innovators were working to address the quality gap between offset vs. digital printing. The development of UV inks was a game-changer. These are specially formulated inks that quickly dry when exposed to ultraviolet light rather than oxygen.
UV inks dry much faster and produce far more brilliant colors than conventional inks, leading to far crisper and clearer printing results. UV inks are also based on the four-color CMYK, delivering vastly improved color matching. And UV printing can be used to print on paper, cardboard, plastic, vinyl, acrylic, metal, and more.
Digital printing using UV inks is generally called UV printing or digital UV printing. While offset printing maintains a slight edge on image printing quality, digital UV printing has narrowed the gap significantly, and the technology is still new. Affordability, speed, quality, and versatility make digital UV printing the best choice for most printing projects. And now, large format UV printers have overcome the disparity in size that existed in offset vs. digital printing.