Four Color Process Printing

While other printing processes like letterpress or screen printing are great options for producing your work, this article will discuss offset lithography printing specifically, which is the more standard means of producing most any printed work in mass quantities.
Offset lithography is a process that uses a combination of four process colors, cyan, magenta, yellow, and black, generally noted as CMYK, to produce full-color images. Spot colors, standardized by the Pantone Matching System®, are also available in offset printing, but know that when creating your documents, you need to be sure of two basic image guidelines.

Get the Mode Right

First, always make sure that each and every photo or image you include (both raster and vector) are in CMYK format and not RGB. While RBG offers a greater color range and works well in designing for implementation online, it doesn’t cut it when going to press. Any images that you leave in RGB mode will have to be translated into CMYK by your prepress operator before going to print. This not only takes more time for a prepress technician, but leaves you unsure as to how your color will turn out once on press.

Getting the fonts right

In any standard layout program, there’s a font bar where all of the options for choosing a font and it’s characteristics can be found. Included in this bar is usually a drop down menu for selecting your font name, along with other attributes, such as leading and kerning, font weight, and paragraph alignment. Some of these programs, like Quark, include drop down menus that allow you to apply characteristics like “bold” or “italic” even when the font you’ve chosen doesn’t include those particular styles.
For instance, if you have the Tahoma font family installed on your system, which happens to include only Tahoma Regular and Tahoma Bold, this extra drop down menu might allow to you to turn it into an italicized font. Even though this is tempting, don’t ever do this when creating a document to send to print. When your printer receives the file and sends it to press, the font will be replaced by a font that is in its system and remove the italic attribute (or any other that you’ve applied arbitrarily). Therefore, always remember to choose a specific font that already has the attributes you’re looking to apply included in the actual font family.

Image Quality

It shouldn’t have to be said, but 72 dpi (dots per inch) will not produce a quality image on press like it will online. Surprisingly, this is a consistent issue prepress operators face in handling images. Always be sure that each of your images is set to at least 300 dpi before sending them to your printer, or you’ll be sadly disappointed when a gorgeous photo you spent hours editing turns out blurry and pixelated once it’s in your hands.

One of These Blacks is Not Like the Other

Interestingly enough, there are actually several different types of black when it comes to printing, but the two most widely used terms are “plain black” and “rich” or “full black.” Keep in mind, “rich black” has several variants, depending on your printer’s preference. If you’ve ever created an image in Illustrator that contained sections of black, and later placed it into a Photoshop document where the image sat on top of a black you chose from the color palette in Photoshop, it’s likely you’ve seen this disconnect.

Plain Black

When you use black in a program like Illustrator or InDesign without choosing a Pantone color, the CMYK breakdown automatically defaults to C=0 M=0 Y=0 K=100, where black is fully saturated and the other three are completely absent.

Rich and Full Black

As stated before, there are several variants of rich black, but what’s important to know when you’re designing is that the Photoshop default for black is different than other programs (where C: 75, M: 68, Y: 67, K: 90). It’s likely that Photoshop will be the place you find this difference most often if you’re not intentionally trying to give a piece of your design a darker, richer tone than you get with plain black.
If you are intentionally doing so, make sure to ask your printer which variant of rich black they like to use on press, usually referred to as “warm black” or “cool black,” where there are higher levels of either magenta or cyan, respectively. It’s generally not recommended that you use a completely saturated level of all four colors (where C: 100, M: 100, Y: 100, K:100), as this can over-saturate the paper on press and will certainly give the press operator trouble.

Why it Matters

Other than over-saturating your paper on press or creating a document that has visibly different tones of black than you were expecting, the main headache caused by choosing the wrong black happens in terms of setting type.

As previously mentioned, both Illustrator and InDesign default to plain black, where it’s more often recommended you do your type setting for documents anyway. If, however, something happens where you’ve accidentally set especially large amounts of type in any variant of rich black, you might notice a problem in your final printed piece. If your press operator runs your job and doesn’t perfectly match up each separation of CMYK by precisely lining up the document’s registration marks, or if the paper shifts at all while moving through the rollers on press, you’ll likely see ghosting of one or all of C, M, or Y falling outside of the characters in your type, making it not nearly as sharp as expected. Your printer might end up doing it well regardless, but it also might take them more time, paper, and energy to print it correctly.