Designing An Advantage: The Inkjet Vocabulary Cheat Sheet
The world of digital inkjet has come a long way in a relatively short amount of time. While pages are still printed on more conventional presses like offset or toner, more pages are being printed on digital inkjet in a wider variety of applications than ever before.
In fact, in The Designer’s Guide to Inkjet, 3rd Edition, authors Elizabeth Gooding and Mary Schilling discuss the growth of inkjet and how it’s replacing static pages on a larger scale.
“What’s really cool about the growth of inkjet is that between 20 and 30 percent of the new pages on inkjet every year are just that — new pages,” explain Gooding and Schilling. “They don’t replace something else, and they don’t fit nicely into the definition of books, direct mail, catalogs, or collateral. As designers embrace inkjet, exciting new applications are emerging.”
The rapid evolution of digital inkjet over the last decade is bound to leave designers a little confused, especially because the relationship between ink and paper is so critical with digital inkjet. This handy cheat sheet offers a quick, concise look at a few important terms to keep in mind when designing for digital inkjet.
The technology by which ink is applied to the sheet can play a large role in the image quality and color stability of your piece. The distinct way in which inkjet presses apply ink — not to mention the innovative composition of inkjet ink — make these terms and concepts key in deciding whether your project is right for inkjet.
Binary vs. multi-drop: Whereas offset presses apply ink to the sheet using large, prefabricate plates, inkjet applies colorants to the sheet in small dots via individual printheads. Binary and multi-drop are the two ways inkjet transfers drops to the paper. Binary printheads apply a fixed drop size and volume, while multi-drop applies ink in variable sizes and volumes.
Dot vs. drop: With inkjet, the difference between a dot and a drop of ink is often conflated or misused, and understanding the difference is key to how this kind of digital printing works. A drop of ink is what comes out of the inkjet printhead, and a dot is what the ink becomes once it hits the sheet.
Dot gain: The amount by which the diameter of a dot of ink increases when applied to a sheet, dot gain will make the printed midtones appear darker and less crisp as the dots absorb and spread into the paper. Because paper formulated for inkjet dries quickly, less ink absorbs into the sheet, which would help maintain superior image clarity and color quality.
Drop volume: Drop volume is how printers discuss the size of specific drops of inkjet ink. Drop volume, according to Gooding and Schilling, is important in digital inkjet because the ability to control drop volume on an inkjet press means “you optimize quality levels of individual jobs and media types by adjusting drop sizes.”
DPI (dots per inch): Commonly used to discuss overall inkjet quality, DPI expresses the number of dots of ink per square inch of a sheet. DPI is also referred to as the true resolution of an inkjet press, and the versatility of how ink is applied to a sheet means your DPI is variable depending on the job.
Total Area Coverage (TAC): An extremely important concept with inkjet, TAC describes the total thickness of combined ink in any given area of the sheet. The aqueous nature of inkjet ink combined with the ability of different paper stocks to hold certain thicknesses makes TAC critical in avoiding issues with the ink not drying properly, some of which include show-through or paper curl.
Speaking of paper, the type of sheet you choose for inkjet can greatly affect the quality of your print. The wrong marriage of paper and ink in digital inkjet can result in a number of visual defects, some of which include cockling (ripples in a sheet as a result of too much moisture), curling (structural damage to the sheet itself), or feathering (fuzzy images from negative interactions between ink and paper fibers).
Keeping these couple paper terms that are unique to inkjet in your back pocket will help you avoid these unsightly outcomes.
Inkjet coated paper: Formulated specifically for inkjet, inkjet coated sheets come in a variety of surface finishes from very shiny (gloss) to less shiny (matte). The surface of inkjet coated stocks dries very quickly, which helps create a broader range of colors compared to uncoated sheets. The unique coating also helps make inkjet coated sheets more resistant to dirt, moisture, and wear.
Inkjet treated paper: Inkjet treated paper uses a treatment that blankets and seals the wood fibers. These treatments separate the colorants from their carrier liquids, which better allows the colorant to remain on the surface of the sheet and thus create better print and image quality. Inkjet treated sheets also have a reduced porosity to prevent the ink from absorbing into the sheet along with the carrier liquid.
Porosity: The ability of the sheet to absorb ink or water, the porosity of paper is critical with inkjet given the aqueous nature of the ink this type of press uses. For example, uncoated paper — sometimes called offset paper — has a much higher porosity because the fibers are not sealed, which makes uncoated sheets problematic for both color quality and stability with inkjet inks.
Precoating: A special type of coating or finishing that is applied before ink is applied to a sheet, a precoating can be applied from an inkjet printhead via plate, roll, or jet. A precoating can be added to a sheet that is not specifically formulated for inkjet to make the paper more compatible with the aqueous nature and application process of inkjet ink. Precoating can also be referred to as a primer.
There’s so much to understand about how to properly design for the world of the digital inkjet, and while this gives you a good foundation, it’s really just the beginning.
The Designer’s Guide to Inkjet, 3rd Edition, provides a comprehensive look at what you need to know to master the process of designing high-quality print specifically for inkjet. Download the guide to read more.