Friday, November 18, 2011

Spot Color vs. 4-Color Process

As a continuation of our previous post, I will discuss the differences between two printing processes: Spot color and 4-color. Depending on the type of artwork that will be used for the custom printed paper roll job, one process may be a better fit than another. In this post I will give a basic overview of spot color and 4-color printing.

Spot Color consists of printing with one or more solid pre-mixed colors. The ink is printed directly on the paper or substraight. We use the Pantone Matching System (PMS) as our reference chart. PMS lists consist of colors with an ID number and the color mix or recipe to create that color. For Example PMS #2945 uses 60.6 parts of Process Blue, 36.4 parts of Reflex Blue and 3.0 parts of Black to create that shade. PMS colors are shown for both coated and uncoated media. Spot color printing is effective for reproducing logos or simple graphics. We can print spot colors in up to 3-5 colors on the back and front side of the sheet. A PMS color chart can be found here:

When using multiple spot colors sometimes trapping (adding a slight overlap between colors) is used to avoid gaps between colors.

Overprinting can also be used, which involves colors being printed on top of one another. The diagram to the left shows the differences in printing methods:

4-color process printing uses screens to separate colors. The press can print dots on top of dots to mix colors to create the illusion of many more colors, thus helping to attain photographic types of images or graphics with lots of color depth. The following four colors are used by the printing press: Cyan (a blue-green color), Magenta (a reddish-pink color), Yellow and Black (CMYK).

Below you will see how the combination of Cyan, Magenta, Yellow and Black printing plates create a full color photo:

Take a close look at the dots used to mix the colors.

Please keep in mind that these printing abilities are available, but are dependent on what you have in mind for your custom printed project. A receipt that features a photo may need a 4-color process job, while a simple one or two color logo may lend itself more to a spot color job. If you have any questions or if you would like to discuss a specific idea you please call us to discuss in more detail.