Designing for Digital Printing - Part 2
Last month we listed the various digital presses currently on the market: xerographic presses such as the Indigo, direct-imaging presses such as the Heidelberg DI press, and ink-jet presses. Although we described a few good ways to maximize the virtues and minimize the flaws of the first two, we didn’t address ink-jet technologies.
Let’s start off with ink-jet presses this time. Most of you use an inkjet printer in your home in conjunction with your desktop computer. Minuscule droplets of ink are sprayed onto the substrate from tiny ink-nozzles as the paper goes through the printer. The cost of the printer is minimal. The cost of the ink cartridges is often very high, and the quality of the output is exceptional. Most printers now use this technology for contract proofs.
Color fidelity is an issue with ink-jet printers, as it is with xerographic presses like the Indigo. For a long time ink-jet colors were composed of the four process hues: cyan, magenta, yellow, and black. Since process color builds do not exactly match many of the PMS colors, ink-jet manufacturers began to widen their color set. One large format ink-jet proofing device now on the market supports eight ink colors: magenta, light magenta, cyan, light cyan, yellow, and three blacks (black; light black; and light, light black). Such new technology can match a wide range of spot colors dead on. This makes them fabulous digital (no film needed) proof printers.
Designing for an ink-jet press is not that different from designing for any other ink-based (including offset) process, except that in most cases you are printing only a limited number of copies of your art file. This is due to the fact that page for page, xerographic-press output is cheaper than ink-jet output since toner is less expensive than ink.
WHEN WOULD YOU USE A LARGE FORMAT INK-JET PRINTER?
You might use a large format ink-jet printer (and the one noted above is 64” wide) for a banner to be hung on the outside wall of a building. In this case, in addition to design issues, you would be thinking about such qualities as light-fastness and weather-resistance. For instance, you might choose to print a 13-foot by 17-foot banner in strips on a vinyl substrate that you would then stitch together into the final-sized product. Since it is an outdoor piece, you might choose solvent-based pigmented inks rather than water-based dyes so that your banner would hold up to the sun, the rain, and the wind.
Or you may choose to hire a sign vendor with a large-format flatbed ink-jet printer. You could print a huge indoor sign on a rigid substrate with such a press.
But again, unless you’re printing a number of copies at home on a small ink-jet printer, you are choosing the ink-jet process to print one copy (or a limited number of copies) of something, whether it is a contract proof of a poster, an indoor or outdoor sign, or display materials. You might even print an image in food dyes on the icing of a cake.
Unlike a design for a xerographic press, a design for an ink-jet press will not need to be altered much to be “printer-friendly.”
GENERAL GUIDELINES AND TRICKS
Nevertheless, designs for ink-jet and xerographic presses can benefit from a few tips and tricks.
Consider the resolution of the final piece when choosing type sizes. For a wall-size banner, your type and images will appear a little fuzzy when seen close up (due to the size and lower resolution of the huge-format final product); however, from viewing distance they will be crisp. Discuss type size and image resolution with your print provider.
Small publications are a different story. Type smaller than 4 points may be rendered fuzzy in a brochure produced with either ink-jet or xerographic technology. As a rule of thumb, most people will want to see their type in 10- or 12-point size to facilitate reading.
The same problem may arise when you reverse small type out of a heavy-coverage background. If the background is made up of large amounts of all press colors (cyan, magenta, yellow, and black) and the type is not only small but also has serifs, the serifs may fill in. In general, digital presses are not as forgiving as offset presses when you are reversing small type out of a large, heavy solid. This is due to the size of the toner particles, even in a high-resolution xerographic press. The best way to avoid this unfortunate result is to increase the point size of the type a little and print the text in a sans serif face. Printing on a brilliant white sheet will also help (since the substrate will show through) as will playing with the amounts of ink you specify for rich blacks. More C, M, Y, and K will make the solids rich but may fill in the type; less of each ink will reduce the chance that the reversed type will fill in.
Finally, it is generally prudent to use tints of black ranging from 20 percent to 80 percent. Using a 10-percent screen of black may wash out the tint, and a greater than 80-percent tint may fill in to form a solid. As you see, balance is of utmost importance.
This is a two-part article. Look for more information on designing for digital presses (including ink-jet presses) in April 2008 issue of Quick Tips.
[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]