Four color process printing uses the subtractive primary ink colors of cyan, magenta, and yellow plus black ink. This is abbreviated as CMYK or 4C. CMYK is the most widely used offset and digital color printing process.
High Fidelity Color Printing:
High fidelity color printing refers to color printing beyond just the four process colors of CMYK. Adding additional ink colors results in crisper, more colorful images or allows for more special effects. There are several ways to achieve more vibrant colors or a greater range of colors.
In general, conventional offset printing is more time-consuming than digital printing. With offset printing, separate printing plates must be prepared for each color of ink. It is best suited to large runs. Digital printing can be more economical for shorter runs. Whichever method you use, the more ink colors the greater the time and expense usually. As with any printing job, aways talk to your printing service and get multiple quotes.
4C plus Spot:
One way of extending the options available for color printing is to use the four process colors along with one or more spot colors -- pre-mixed inks of a specific color including metallics and fluorescents. This spot color may not be a color at all. It could be an overprint varnish such as an Aqueous Coating used for special effects. This is a good option when you need full color photos but also need precise color matching of a company logo or another image with a very specific color that may be hard to reproduce with CMYK alone.
The digital Hexachrome printing process uses CMYK inks plus Orange and Green inks. With Hexachrome you have a wider color gamut and it may produce better, more vibrant images than 4C alone.
This six color digital color printing process uses CMYK inks plus a lighter shade of cyan (LC) and magenta (LM) to create more photo-realistic images.
In addition to CMYK, LC, and LM this process adds a diluted yellow (LY) and black (LK) for even more photo-realism, less graininess, and smoother gradients.
Before preparing a print project for 6C or 8C process printing, talk to your printing service. Not all printers offer 6C/8C process printing or may only offer specific types of digital and/or offset color printing, such as only digital Hexachrome. Additionally, your printer can tell you how best to handle color separations and other prepress tasks when preparing files for 6C or 8C process color printing.
Dig Deeper Into 6C and 8C Printing:
Resources and more details on color printing beyond CMYK.