I haven’t stirred the pot in awhile, so I thought I’d take a few swipes around the edges today. I’m currently updating my customer education primer, “Digital Printing: Transforming Document Management and Marketing” and would like input from Digital Nirvana readers on what you believe to be the most important visual differences between digital and offset printing.
Here’s what I wrote. What do you think?
Visual differences from offset
This might sound like a big “duh!” so why mention it? The issue of offset versus digital quality has dogged this marketplace for more than a decade, so it’s necessary to at least give it a nod. Yes, digital quality is not the same as offset. It’s close, but not identical.
For extremely high-end jobs, such as annual reports, the choice is almost always offset, regardless of run length or price, but few applications fall into this category. Even many commercial photo books are now being produced digitally. The output won’t be identical to high-end sheetfed, but there are digital technologies that get awfully close. Some practitioners claim that, in some cases, digital production quality is actually superior.
In terms of appearance, one of the most basic differences between digital and offset arises because most digital presses apply dry toner on top of the paper, while offset uses liquid ink that soaks into it. Thus, sheets printed with dry toner can have a slightly brighter, glossier appearance (unless the sheet is coated, in which case the coating masks any differences in gloss between the two). If you run your finger across the top of the sheet, you may feel a slightly unevenness that comes from the differing layers of toner. In the sheetfed market, HP Indigo presses are distinguished by their use of a liquid toner that soaks into the paper much like ink. This gives the prints a more offset-like appearance.
In the high-speed, high-resolution inkjet market, one of the issues is color saturation. More water in the inks means greater challenges with drying, especially with high percentages of ink coverage. In the lower resolution (lower ink coverage) transpromo market, this is not an issue. But in the textbook market, this is why we’re seeing these presses used more heavily for higher education than for the more graphics-heavy K–12 textbooks. The imaging technology of the high-speed, high resolution inkjet machines (as opposed to the lower resolution transpromo machines) is still being refined, but certainly, the issues of heavy ink coverage and dry time will be addressed over time.
There are other subtle differences between digital and offset, such as scattering of toner around the edges of text, but marketers—and consumers—are unlikely to notice them unless they know what they are looking for and are looking through a loupe.
Keep in mind, too, that “difference” doesn’t mean “bad.” There are those, even experts in the printing industry, who actually prefer the appearance of digital print for some applications.