Navigating the Labyrinth

Editor’s Note: This is Part 1 of a two-part series on purchasing digital presses.

The decision to purchase a digital press can be stressful. Manufacturers (and even distributors) must answer some critical questions to ensure the selection process is successful.

Applications
What applications will be produced on the press? This is a complicated question, because the answer might change over time due to customers’ changing business needs and their willingness to embrace new applications. However, some variables can be determined in advance. For instance, will the jobs be transactional or commercial? If the plan is to produce transactional applications, then high-speed presses using Advanced Function Presentation (AFP) workflows are needed. Consider whether the press should enable cut sheet or continuous feeds, monochrome or spot color, and whether data will be processed natively or converted.

The products produced also affect the front-end, printing and finishing capabilities the press will need. Unless you specialize in a single application, you’ll need a flexible machine that allows you to cross market platforms. If you use the machine largely for a single application, look closely at the special features offered by each manufacturer. For example, if you print a lot of photo books, HP recently introduced a new solution for driving multiple presses doing photo albums, including image enhancement capabilities.

Its 7-color machines also offer a light magenta often considered critical for achieving the true photographic look.
Offering digital printing doesn’t mean that you must also offer color. Many short-run applications, including 1-to-1 personalization jobs, are run black-and-white or imprinted monochrome onto full-color, offset-printed shells.

Conversely, transactional jobs aren’t necessarily colorless. An increasing number of transactional jobs now offer highlight color. The introduction of high-speed, modular presses such as the inkjet Kodak Versamark means that high-speed production can now be done in 4-color.

New or Existing Products
Will the the digital press provide production flexibility for existing product lines? Or is it for expanding into new areas? Some manufacturers are moving out of existing product lines into new applications and areas of profitability. Others simply take existing applications and produce shorter runs of these same jobs more efficiently by transferring volume from small-format offset equipment to digital equipment.

Whichever model you need, purchasing a digital press starts with knowing what applications you’ll produce, and these applications depend on what markets you’ll serve. If you haven’t performed a market analysis to determine what digital applications would benefit your target markets most, then you aren’t ready to buy a digital press. Even if your intention is to stick with existing product lines, things change. Keep flexibility for unexpected applications in mind.

The formats and substrates your products require will determine the output size of the press. For example, a rollfed press offers greater flexibility for banner printing and other over-sized jobs. If you print high-volume postcards, look at presses with format sizes that allow you to do more “up,” or presses that offer UV coating inline. Some presses handle a wider range of substrates than others. If your applications require certain types or weights of stock, you may have to work backwards to find the appropriate press.

If you plan to do mostly short-run jobs, you’ll require a different workflow than longer-run jobs. The shorter the run, the higher the percentage of time required to set up and process it. Therefore, if you have a high volume of these jobs, many of the efficiency-enhancing features of today’s digital front ends (DFEs) have a greater impact on the purchase decision because they directly affect the total cost of the job.

If you buy the press primarily for the needs of a single customer whose volumes will justify its purchase, look to press vendors who either have off-the-shelf solutions or are willing to customize the press for that customer’s application. This also opens the possibility for inline finishing solutions, which vary widely by manufacturer.

File Formats
Knowing which file formats the press can handle is a workflow and applications issue. For example, all digital presses can handle VDP jobs using PostScript, but PostScript isn’t the most efficient way to handle high-volume or complex jobs.

If you’re printing 1-to-1 marketing applications, the file formats your DFE can process make a difference. You might want a press that handles page description languages such as Xerox’s variable-data intelligent PostScript printware (VIPP), HP Indigo’s JLYT (pronounced Jay-layout), or Creo’s Variable Print Specification (VPS). These languages are optimized for high-volume environments. If you’re running PPML (an open standard for producing VDP jobs), which operates in a similar fashion to the vendors’ proprietary high-speed VDP processing languages, there are variants that not all presses support. Some presses support PPML/VDX (variable data exchange standards), while others support PPML/GA (graphic arts).

To print transactional documents, AFP workflows (or, coming soon, Open AFP) may be required for the most efficient processing. If you print transactional and commercial work, you may want a press that processes AFP or PostScript, or work with an architecture such as Xerox VIPP that can handle both since the controller will cache high volumes of page elements so that each element doesn’t have to be re-RIPed.

Moving toward a fully integrated workflow, you might want the press to handle JDF. If you deal with high volumes of customized documents, look into Optimized PDF, which is a caching function within PDF that allows reuse of some elements, so the entire PDF doesn’t have to be RIPed each time.

Digital Front End
All digital presses have a digital front end, the command and control center. With the DFE, you can manage jobs, control the queue, impose pages, and select and assemble components of the job, and these tasks vary significantly by manufacturer. Some press controllers have embedded imposition architectures and tools. Others have output management controls that allow them to send jobs to different presses. Some have sophisticated color management. Others ingest VDP files in different ways: Handling page description languages (such as PPML) that others can’t, for example.

The more complex the application, especially for high-volume VDP, the more critical the DFE. For example, some DFEs pull together the necessary images and build graphics on the fly so that the press receives a fully composed document. If the press were responsible for handling functions alone, it wouldn’t print anywhere close to the maximum rated speed.

Of course, the necessity of these and other functions depends on applications and volumes. If you plan to print relatively short runs of less complex jobs, the DFE is far less important.

Every DFE has its own special features that optimize workflows for different applications. Xerox’s DFE, for example, has a feature that allows manufacturers to impose a Z-sort at the controller that maximizes postal efficiencies for postcard printing. Essentially, the job is printed in the way that the cards will eventually be mailed for lowest postage rates. For manufacturers looking to move into direct mail, this feature could have a direct impact on profitability.

Print Quality and Colors
Clients who demand the “best” print quality, even from their shortest runs, have a subjective view. All of the high-end digital presses have near offset quality, and which is “the best” often is in the eye of the beholder. If you print a lot of photographs, the smaller toner particle size of the HP presses, as well as the liquid toner (which partially is absorbed by paper, thus giving it more of an offset look) is often favored by many clients, but there are no hard and fast rules.

Somewhat related to print quality is the performance of the toners on the finished sheet. Although the differences are subtle, some toners crack more than others across the fold, or they vary in their adherence to the sheet, which has an impact on scuffing and scratch-resistance. Be sure to perform a scratch test on your printed samples, especially if many of your pieces will go through the mail.

Unlike offset presses, most digital presses are 4-color. HP presses offer up to seven colors, but the fifth units in other presses, such as Nexpress, are used for coating. Some presses have better color matching systems than others. If corporate colors are important to you, you’ll want to do a lot of sampling. One thing to keep in mind is that especially for short-run jobs, changing out the fifth or sixth color can be deadly to prep time. Profit margins on short-run jobs can quickly disappear by swapping out match colors, which is one reason why most digital presses are 4-color only. For most applications, color matching is secondary to turnaround time and the value of the overall application, such as 1-to-1 messaging or inventory management.

One solution for manufacturers who anticipate a high percentage of their jobs requiring corporate colors or special color requirements is to purchase a press with a Hi-Fi color system. Currently, the only presses offering this option are from HP (using its HP Indigo Indichrome color system).

Running Speed
The higher the job volume, the more important the press running speed. It’s important to remember that the rated press speed is just a number. It doesn’t mean that you’ll run jobs at this speed. If you don’t have a front-end workflow that optimizes the assembly and processing of complex VDP jobs, your once super-fast press can bog down. If you print a high volume of short-run jobs, the front-end processing of those jobs can kill your productivity, even if, once the jobs are in the print queue, they can be output quickly.

If you have complex or high-volume jobs, look extra carefully at PDLs and print controllers.

This article is reprinted from the January 2007 issue of PERF Report, a newsletter focused on industry-specific research. Visit www.theperf.org.