Four-color process printing, also known as CMYK or 4C, is the most widely used digital and offset color printing process, in which the visible color range is replicated from four basic colors: cyan, magenta, yellow and black.
In today’s market, four-color process printing comes in many forms — and sometimes, confusingly, with more than four colors!
While many printers have offset presses with only the four basic CMYK colors, many have capacity for 2-4 additional ink positions reserved for “spot” colors (any color ink, pure or mixed, that is printed in a single pass). These spot colors can include pre-mixed inks such as Pantone inks, metallics, fluorescents — or in fact, may not be a color at all.A colorless varnish may be used as a spot "color," either printed over the other inks to add durability or to provide special visual effects on the printed piece.
And not all process color printing is created the same way!
Offset 4C printing allows for the selective use of spot colors, but can require more up-front time due to prepress preparation. But once the job goes on press, this production method is still the speediest, and delivers the lowest per-unit cost at higher quantities.
Digital 4C printing, while requiring less prep time and less ink, produces a grainier result with a smaller visible color spectrum, and ultimately is slower to produce on press. At present, it also presents format restrictions, as the most widely used digital presses are typically limited to 12x18-sized sheets.
Depending on the format of the printed piece, digital 4C printing is usually more cost efficient at quantities of 500 units and below, while offset 4C printing affords a lower unit cost at quantities of 2500 and up. When deciding between digital or offset printing, cost and speed of production would be weighed against color vibrancy and the need for spot color usage. If price is the most important concern, and the quantity is somewhere between 500 and 2500, consider pricing a print job with both digital and offset printers to be sure you’re getting the best value.
Coming next time: Beyond Process Color: Hexachrome, Stochastic, and more!

