What is 4 Color Process Printing?
The Illusion of Full Color Printing
Does the term 4 color process printing mean that only four colors appear on a printed page? Interestingly, the answer is yes and no. Let's see why.
Full color printing (as 4 color printing is often called) is created by the combination, density and placement of dots of only four colors of ink on a paper or other surface: Cyan (a light bright blue), Magenta (a ruby looking red), Yellow (bright yellow) and Black. Those specific dot placements create almost all the colors one could ever want to print. People who have ink jet printers will recognize these four colors since each one has a separate ink cartridge... and they can see the results of what happens when one of the cartridges runs out of ink!
This is usually known as CMYK or 4 color process in the printing world. Note that CMYK is an acronym... sort of. The first three initials—CMY—stand for the three ink colors of Cyan, Magenta and Yellow. The last initial—K—stands for "Key" or "Key Plate" which is the black ink detail layer. Unlike an ink jet printer which could apply the droplets of ink through one printer head, a printing company who does full 4 color printing applies the dots of ink one color layer at a time. But that doesn't mean it's a slow process. The speed at which this happens in large print operations can be split seconds!
Therefore, all the colors and images one sees when viewing a printed page are really just dots of Cyan, Magenta, Yellow and Black ink. Because of their placement, the human eye interprets the printed dots as colors. So full color printing is really an illusion.
What's the "/" Mean in 4/Color?
Sometimes 4 color printing will be shown with a slash after the 4 as in "4/color." However, that's usually not correct, since the slash usually refers to the number of colors that would be on the back side of the printed page.
For example, the abbreviation 4/1 would signify 4 colors on the front side and 1 color on the back. In the print arena, this would commonly referred to as "4 over 1." Similarly, 4/4 means that the job is full 4 color on both sides of the printed page.
What is a PMS Color?
Particularly for spot printing, specially formulated inks may be used to get a desired effect or more accurate color. These colors usually are formulated according to the Pantone® Matching System (PMS) which assigns a special number to each color. An example of when a PMS color might be used is to exactly match a company's logo.
Because ordering a special PMS ink can add to the cost of a print job, a PMS match color—a combination of the CMYK colors—can be used in full color printing to create the color. While this usually creates acceptable results, it may be slightly off from the pure PMS ink. Weigh the cost of the ink, special design considerations and budget to determine if a pure ink or a match is the best choice for promoting the company's brand.
What is 2 Color Printing?
To save money, especially in years past, marketers would often choose 2 color printing, commonly referred to as spot printing. However, there are two ways that 2 color printing can be done:
- Using a combination of two of the CMYK inks, such as Cyan and Black (C and K, respectively).
- Two custom formulated ink colors (such as PMS inks discussed earlier).
- One CMYK ink and one custom formulated ink.
Similarly, 3 color printing can use combinations of CMYK and PMS inks to achieve desired effects.
However, today, the cost of 4 color process printing has become so reasonable due to technological improvements that going with 2 color and 3 color printing may not offer a significant savings! Costs for doing full color and spot color printing should be compared prior to creating the graphic design and layout.
What is 6 Color Printing?
If CMYK 4 color process printing can create any color desired, what advantages would 6 color printing offer? And six is not the highest number of colors that can be printed! There are even 10 color presses!
The extra colors can be spot PMS colors to help match branding colors since sometimes blending CMYK inks cannot produce the desired color effect. In other jobs, the extra "colors" may be varnishes to coat the entire sheet or just certain areas to create a special effect with contrasting shine levels.
A 6 or 10 color printing job is not an average print run! (And it can be VERY costly.) It is a complex project best left to the printing, graphic design and advertising pros.
"The Color Looks Funny on My Computer Screen. Why?"
Today, proof copies for approval of printing projects are usually sent as PDF files for review. While the speed and convenience of this proofing procedure is outstanding, it can sometimes be disappointing for those who are looking at the PDF on a computer screen. The color may look off, regardless of whether the color was created as a CMYK equivalent or a solid PMS ink. Plus, it will typically print accurately regardless of how it looks on the screen.
The reason for this is that computer screens simulate CMYK color images through the RGB (red, green, blue) color technology used for the screen. So what is seen on the screen is merely an approximation of what it will look like when actually printed. There are programs that can calibrate screens for various levels of color accuracy; however, those are primarily used by print and graphic design professionals.
For print projects where true, authentic color is an absolute necessity, or the cost of the print run is extremely high (usually when distribution and dollars are in the several thousands), a physical print production proof should be ordered to approve prior to the entire print run. As well, these proofs may be viewed in specially lighted viewing booths and the reviewer may use a loupe, a small high powered magnifying glass, that can show the placement of the CMYK or other ink dots. Usually this takes the well trained eye of a print, graphic design or advertising professional.
When color accuracy is not as crucial, such as for many small business projects, the onscreen PDF proof may be sufficient with the understanding that the actual printed piece may have color variations.
Realize that sometimes there may be additional costs for proofs, depending on the type or complexity of the proof required.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
© 2014 Heidi Thorne