When to Use Spot Colors (Such as PMS Colors)
If your project meets one or more of the criteria below, spot colors may make the most sense:
The publication has no full-color photographs and uses only one or two colors (including one spot color plus black).The publication needs a color that cannot be accurately reproduced with CMYK inks, such as precise color matching of a corporate typeface or logo color.To print a specific color over multiple pages that require page-to-page consistency.To print over a large area, such as a poster (spot color inks may provide more even coverage).The publication needs more vibrant colors or more exact color matching than what CMYK inks produce.The project requires special effects such as metallic or fluorescent spot inks.
When to Use Process Colors (CMYK)
You may want to use process colors when the following conditions are present:
The publication uses full-color photographs.The publication includes multi-color graphics that would require many colors of ink to reproduce with spot colors.The publication needs more than two spot colors. Check with your printer; process color printing can be less expensive than using three or more spot colors.
When to Use Process and Spot Colors Together
CMYK can produce many colors but not every possible one. Many publications are printed using a fifth color. Here are some examples:
A publication with full-color photographs must incorporate specific spot colors that can’t be created with CMYK inks (such as a logo color or a metallic ink).To enhance or increase the intensity of (bump up) a specific process color by adding a spot color ink to it (a fifth plate for the spot color used in this manner is called a bump plate or touch plate).To produce a full-color book or brochure but in different language versions (variable printing). Everything but the variable text is printed using CMYK, then some of the shells are printed using a black spot color for the text in one language, other shells are printed in another language.Portions of a full-color publication are coated with a clear varnish (the varnish is specified as a spot color).
When to Use 6-Color or 8-Color Process Printing
If you’re going for some of these specific results, you may want to use 6-color or 8-color process printing. Here are a few examples:
When you want clearer, more vibrant, photo-realistic colors than can be achieved with 4-color (CMYK) printing alone. When you want to get more pure violets, greens, and oranges than are possible with CMYK alone. When you need multiple specific colors along with photos. Almost 90% of PANTONE spot colors can be closely simulated with 6C/8C high fidelity printing (compared to 50% with CMYK alone).