Once the determination has been made for a publication to be printed via offset press or lithography, the next decision is usually whether to print using spot or process color. Knowing how and why to use one over the other will help you make that choice when creating your print collateral design.
Process color (also called four-color, 4-color, or full-color) uses four base inks of cyan, magenta, yellow, and black (CMYK) and halftone printing plates to reproduce a wide range of possible colors. In contrast, spot color uses a pre-mixed color applied on separate printing plates, one for each color needed. Magazines often use process color, which allows the designers to reproduce a full spectrum of color, including accurate photographs; alternatively, business cards that have black type and a logo in black and red would be a prime example of a spot color job.
Spot color is ideal when a color has to be consistent across all media and from one print run to the next. Because the ink is pre-mixed using a standard such as the Pantone Matching System (PMS), there should be no variation between print jobs. When using a spot color, you are limited to shades or tints of that color, giving you a much narrower spectrum. It’s possible to achieve the effect of more colors by combining spot colors or incorporating duotones; however, once you have more than two spot colors plus black (black is often the main spot color used), the process color route tends to be the more cost effective way to go.
The benefits of process color
Process color’s biggest draw is that the wide range of colors means almost any shade you mix in your design software can be re-created using the four-color method. When creating colors, be sure you are working in the CMYK color space, as many colors created with RGB can’t be reproduced faithfully in CMYK’s narrower color spectrum. In the last decade or so, the costs involved in printing process jobs have come down significantly, making them more common than spot color jobs these days.
Combining process and spot in the same publication
You can also combine both process and spot printing in the same publication. You may want the flexibility of using process to deliver a wide range of colors and to reproduce color photos while also accurately presenting your company’s trademark blue logo. In this case, you would end up with a “four plus one” job, using process for everything except the logo, which would use a spot color plate. Another application for a spot plate—either with other spot colors or process colors—is the use of specialty inks or varnishes. A common practice is to print a process job but put a matte varnish over photos or logos to make them stand out. The varnish plate acts as a spot color in this case, and it would need to be set up as such in your page-layout software. If you need colors that can’t be reproduced with CMYK, like metallics or fluorescents, they would need to be run as spot colors as well.
As with all design jobs, knowing what the finished piece needs to look like and what effects you’re after ahead of time will inform decisions you make from start to finish. Once you’ve chosen which color route to take, you can design appropriately for that method.