Process Color vs PMS Color Explained

Written by Geoffrey Eisenberg, Vice President of Operations at Tidewater Direct

A color is primarily replicated one of two ways in the web offset printing process; process color or Pantone Matching System (PMS) color. Understanding the differences are critical to extracting the best possible quality out of your print campaign.

Process color, also known as “4cp” is achieved by laying down cyan, magenta, yellow and black on top of each other in a sequence to produce an image. Each printing plate is specially created in the prepress process to attract the perfect amount of ink to replicate the image. Almost all magazines, catalogs, and publications are produced using process color, where there may be an infinite number of colors to reproduce. By examining full color print through a loupe or magnifying glass, you should be able to see thousands of little dots that are arranged to make up the image. Process color generally requires 4 printing plates for each side of the printing surface – one for each color.

A PMS color, also known as a “spot” color, is an ink color that replicates the intended color exactly. A PMS color is called for when color variance simply won’t do, like Coca-Cola red or Southwest yellow; in other words, for branding purposes. PMS colors, have numbers associated with them like 185 or 287, which can be referenced in Pantone color guide. By selecting a PMS color, you can be sure that from roll to roll of finished product, the color you selected will look the same every time.

Now that we have a framework of understanding between PMS and Process color, it’s important to understand the benefits and disadvantages of each.

Process Color – Benefits

  • The ability to reproduce an infinite number of colors with only 4 plates
  • Relative low cost of ink as compared to PMS mixed colors
  • Hides small imperfections that occur during the printing process, such as hickies and small scratches, because the color is built out of 4 colors
  • Mitigates “ghosting” on challenging artwork as multiple colors make up one

Process Color – Cons

  • When printing text or narrow creative built from 4CP, registration (keeping all colors in the build perfectly aligned) can be challenging on many web offset presses and may not produce acceptable results
  • While some may come very close, PMS colors won’t be replicated exactly as intended
  • The industry standard tolerance for density is ± .05 – when 4 colors are laid down with that tolerance, color variation can occur within a print run

PMS Color – Benefits

  • The ability to replicate a color exactly as intended throughout a print run, mitigating color variance
  • Eliminating registration concerns since there is only one color

PMS Color – Cons

  • Because there is only one color, the potential for small, visible print imperfections becomes greater. Difficult art that lends itself to ghosting may create print issues
  • Most presses are limited to 8 units or less and are intended for 4cp on the top and bottom. As a result, PMS colors are ideal for situations with less than 8 colors. Some presses are 10 color capable, which makes them perfect for running 4cp + 1 spot color on each side.
  • Ink cost is marginally higher

In summary, different situations call for different implementation of process and PMS color. By knowing the advantages and potential pitfalls of each printing process, designers and print buyers can make better decisions on how to create and execute a print campaign.