Offset printing and digital printing are based on similar principles but carried out in very different ways. To fully explain the difference, first we need to jump back in time almost a millennia…
A (Very Brief) History of the Printing Press
The Chinese were hand-printing books with porcelain letters as early as 1040, while metal type was created in the 1300s. But it wasn’t until 1440 that Johannes Gutenberg, a German goldsmith, invented the printing press. (Fun fact: You can see a surviving copy of one of Gutenberg’s printed Bibles at the Library of Congress.)
You can read about the first press in detail, but the basic gist is that the individual pieces of type were set into a frame and swabbed with ink. Then the paper was laid over the frame and the frame and paper together were rolled under a platen that applied the pressure needed to transfer the ink. Hardly seems quick, does it? But remember, prior to the printing press most copies were painstakingly written by hand. Once enough copies of that sheet were printed, the type was reset into the frame and copies of a new page were printed.
Fast forward 450 years, and offset printing was invented in the late 1800s. The idea behind offset printing is that you get sharper images and crisper lines by transferring ink from rubber to paper instead of directly from metal to paper. So metal plates are etched and attached to a large metal cylinder, which transfers the image onto another cylinder covered with a rubber “blanket”, which then makes an impression onto the paper. Offset presses are named as such because of this method of transfer.
The lithographic process is based on the principle that oil and water repel each other. The metal plates are etched in such a way that the oil-based ink adheres to the image areas and water washes the ink away from the non-image areas. Each offset press has a station for a different ink color, and press operators must maintain a delicate balance between the ink and water in each station to make sure the plates and blankets don’t get flooded with one or the other.
Fast forward another 120 years or so and we arrive at the late 1990s/early 2000s. Technology has been advancing at a rapid pace, and digital presses were created. What makes them digital? Instead of developing large film negatives and burning metal plates with UV light, these presses take the graphics and text directly from a computer and print without creating traditional plates. Many also add to the CMYK system (remember when we talked about color theory?) and include orange, green, and/or violet inks to broaden the color spectrum they are able to print.
Which One Should I Use?
Digital presses are fantastic! With less material cost, less waste from setting up, and the capability to print variable data from sheet to sheet, why do we even have offset presses still?
Well, since every job is unique, sometimes the only way you can achieve the look and feel of the job you’ve designed is to use an offset press. If you need to match a PMS color, you’ll have to use an offset press. Digital presses can only build from their base ink colors. Many times this is enough to satisfy the needs of the job, but sometimes you just have to match that PMS color (remember Coca-Cola® red?). Other limitations of digital presses are the type of substrate, or paper, you can print on and the size of the substrate. Most digital presses are on the smaller end, so if you’re designing a really cool 24” wraparound fold, you’ll be on an offset press.
Your salesperson and customer service representative, along with our production team, know how to handle each job that comes in. You can rest assured that we will plan each job for the printing method that achieves the best product at the best price possible.