Printing Tips: Designing for Digital Presses

This story courtesy of PaperSpecs.com.

Designers are taking advantage of the versatility of digital printing more than ever.

The ability to print four-color on shorter print runs gives them a creative freedom their budget might not have allowed on offset presses. As more digital papers enter the market and more print options become available, there are more variables to consider.

Here are some of the most frequently asked questions we receive:

Can I control the paper choices when a job is going to be printed on a digital press?

You can choose any paper that the printing company guarantees will work with their digital press for the type of job you want to print. Don’t worry, though — with digital presses, the selection of possible substrates is larger than ever and the chances are excellent that you will find a paper that you like.

Before the design work begins, talk to the printing company and ask for samples of the papers they recommend. Each digital press manufacturer evaluates and recommends paper selections (coated and uncoated) for their line of equipment. Some printing companies experiment and are willing to guarantee work done on papers they recommend, in addition to the papers the vendors recommend.

As digital printing processes become more popular, digital papers will be available in more colors and finishes. Many mills will introduce a digital sheet based on their existing lines this year. PaperSpecs.com calls out every paper that is suitable for the various digital presses, laser or inkjet printing and makes specking digital papers fast and easy.

I want to use different papers in one job. Is this possible with a digital press?

Yes, but before you make your final decision on the number of different papers, check with the printing company that will be doing the job. You need to find out how many different paper stocks the digital press can accommodate during a print run.

The NexPress 2100, for example, can handle up to three different paper selections without additional paper handling or manual paper changes. If you specify a higher number of paper stocks than the equipment can handle automatically, you will be charged extra because manual paper changes will be required.

How about Pantone colors?

Most digital presses convert Pantone colors to their CMYK equivalents and print them that way. Some will allow you to specify the conversion formula yourself or allow the press operator to do so. Since Pantone-to-CMYK conversion is also a technique used for offset printing, you may have no problem with the print quality of a converted color.

If you absolutely must have a particular Pantone color, your best bet is the HP Indigo digital press using IndiChrome On-Press and Off-Press color inks, as these are the only Pantone approved digital inks in use on digital presses today.

How can I best proof a job?

Concept proofs can be done in the usual way, which often involves a high quality desktop inkjet printer these days. When you are ready for a more precise proof, ask the printing company to proof the job for you on the press they will use to run the actual job. Unlike traditional offset presses, digital presses are designed to print one-of-a-kind jobs, so they can print a few copies for you as contract or final proofs.

What about large areas of color?

Digital presses that use toner, such as the Xerox iGen and the NexPress, don’t produce large areas of solid color well; some banding or blending problems can occur during a print run. With digital presses that use ink, such as the HP Indigo, these problems may occur, but chances are lessened on these types of presses.

If the design calls for several square inches or more of solid color, introduce a subtle pattern into the solid color or reduce the amount of color used altogether. When in doubt, before you spend a lot of time and money on a design, talk to the printer and ask them to run samples, so you can see for yourself what works and what doesn’t.

I’ve had some problems in the past getting rich blacks from a digital press. Am I doing something wrong?

If you are not happy with the print quality of solid areas of black, you can use a mixture of CMYK, such as 60C, 40M, 40Y, 100K – same as you would for an offset press. By adding in the other colors with the black, you are forcing the press to overload that area with toner or ink. Your blacks will look richer and may have a slight sheen to them.

How do I make white text on a black background look more crisp?

Use the approach I outlined above for the rich blacks, but modify the formula to include less black (K). Depending upon how thin the letter forms and how small the point size is, you may have to experiment with the formula for rich black before you are satisfied. Remember, too, that duller white or colored stock will affect the appearance of white text on a dark background, making the text look less crisp. Use a bright white stock for best results.

How small can the text be and still be readable?

The print resolution of digital presses is improving all the time, so you might be more concerned about how well people can read, the type rather than how well the press can image it! Type sizes of 10 and 12 point, the usual size of body text, will be fine. Avoid using type smaller than four points.

How do I get the best gray shades from a digital press?

Use tints of black, but stay away from 10% black tints unless you want a very light shade of gray. Start with 20% and work your way up to about 80% gray. Avoid large areas (greater than several inches in area) of a single tint of gray.

Should I trap the colors in the file?

Before you take the time to do this, first ask the printer for his recommendations. Make sure to describe the project and how the colors are used or, if you can, show him a concept color proof of the job. Each digital press works differently; some like the NexPress, autotrap all files. Some don’t do any trapping. Follow the printer’s instructions and if trapping is a big concern, run some sample files first.

What about knockouts? Should I anticipate problems?

Problems with knockouts are usually caused by a registration problem on the press. Since digital presses have tightly controlled registration, you should not anticipate problems such as gaps appearing between two colors.

What about bleeds?

Ask the printer if the press he is using has any special bleed requirements for the kind of job you are running. Some jobs, such as those that have die cuts, require larger bleed margins. Most of the time, though, you will be fine if you prepare any necessary bleeds for the job as you would for a traditional offset press. Then, when you submit the job, tell the printer that you have set the bleeds.

Can I use any font I want?

There are so many types of fonts out there, especially on the Web, that’s it’s easy to find a font that won’t work with a digital press — or an imagesetter or CTP device, for that matter. To avoid type problems and the occasional type nightmare, stick with Adobe Type 1 or TrueType fonts. Do not use Multiple Master fonts.

I had a problem with the type on a job and the printer told me I wasn’t using the right type style. What is he talking about?

Type families are groups of type styles — bold, italic, bold italic, demi, condensed and even small cap style. Not every possible style is included in a particular font family or in the set of type families you have purchased.

In order to have your type image correctly, you need to designate the appropriate type style by choosing it from the type or font list. Unfortunately, when you use the bold and italic buttons or select those styles from a menu, the software won’t automatically select the correct type style for you. That would be too sensible, wouldn’t it?

Instead, the software will bold or italicize the plain type style and that can lead to problems with any imaging process.

The photographs in my print job look rough and chunky and that’s not the way I want them to look. What went wrong?

The first thing to suspect is that the resolution of the image was too low for the print resolution. Since digital presses image at 600 dpi or higher, you must make sure the original image was captured by a digital camera or the photograph was scanned at 300 dpi to print with acceptable quality.

You can take a higher resolution scan and lower the resolution to 300 dpi, but don’t try to increase the resolution of a scanned image more than 10 percent. Even though image-editing software allows you to increase resolution with a few keystrokes, increasing it significantly will result in images that look the way you describe — or worse.

What resolution to use, in the capture or scan of a photographic image, is one of the most confusing specifications in the graphic arts because scanning equipment and imaging equipment have evolved over the years. Some printers and graphic artists are still using standards that were applicable years ago with older equipment, but are now outmoded. Don’t be surprised if you hear some “rules” that sound really odd, such as scans must be done at resolutions equal to, or even two or three times, the output resolution.

Another thing to suspect is that the original image was stretched beyond its limits. For images that you want to print on a digital press or a traditional press (as opposed to using them online or in electronic documents), enlarge them no more than 10 percent to 15 percent above the original dimensions. Enlarging them more than this small amount can leave the printing equipment with too little data to fill in the space — resulting in the kinds of problems you’ve noticed.

Special thanks to our friends at Nexpress. For more information, visit www.nexpress.com.

Copyright © 2002-2004 PaperSpecs Inc. All rights reserved.

 

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Posted on: November 18, 2004

2 Comments on Printing Tips: Designing for Digital Presses

  1. while digital printing, the colours come out 2-3 shades darker than it displays on screen..whats going wrong?

  2. Thanks for the tips on printing darker blacks. I’ve had that problem before myself as I was using an RGB format. It was tough to make the change to CMYK, but you have to follow the industry. It’s been a while since I first started working in the print department for my job. I’m amazed at all I’ve learned and how good I’ve become.

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