Preflight: Will Your File Fly

In the beginning was computer-to-plate, which begat digital files, which begat much confusion among graphic designers, printers, and prepress service bureaus because customer files were full of errors and omissions. And there was much weeping and gnashing of teeth until lo and behold, the miracle of preflighting came to pass. And there was great rejoicing because, henceforth, all digital files would be automatically checked and corrected before proceeding to the next step in the workflow, saving many costly remakes and much labor. Hallelujah.

There’s no denying that preflight software has been a godsend for printers and prepress professionals everywhere since the concept was introduced and popularized more than a decade ago. Preflighting is the process by which prepress identifies and corrects missing items and errors in customer files before they become bigger and more costly problems further downstream in the printing process. As the very first stage in a prepress workflow, preflighting generally is performed on the desktop file or on the file right out of the design application to make sure the file will RIP the way it needs to, i.e., will produce a correctly printed job.

Search and destroy

Following a series of automated and manual steps, basic preflighting software checks the un-RIPped digital file for soundness, based on preset or user-defined parameters. Many also offer automatic “correction” of common file problems. (We’ll have more to say about that.) In short, preflighting is the very first stage and linchpin of the prepress workflow that renders the whole process more efficient and productive.

There’s nothing mysterious about why the commercial and package printing industries have spent a great deal of time and money developing automated processes to reduce or eliminate as many process-related errors as possible. According to Doug Rosen, director of education and development for preflight pioneer Markzware, “From the standpoint of ROI [return on investment], (preflighting) makes sense because the earlier you find a problem the less costly it is to repair - even at the final stage when the PDF comes in before printing.”

RIP me, fix me

While preflighting is closely related to both RIPping and file repair, it is synonymous with neither. For example, while RIPping can also highlight problems, it is far better and much less expensive to catch them before a job has been RIPped and output.

According to Gee Ranasinha of DALiM Software, “Most preflighting applications look for certain information, mainly contained in the file’s header, and as long as they find the right things in the right places, they say you’re pretty much ready to print. However, a RIP doesn’t work like that. A RIP has to actually open the file and interpret it, which is why RIPs will sometimes “kick out” a preflighted file.

If preflighting programs work to identify troublesome errors, can file repair be far behind? “The two go hand in hand,” Rosen acknowledges. “Because preflighting is the act of checking a job for completeness, it is associated with reporting and tracking. Fixing is the next logical step after preflighting. If the job passes preflight, then it is ready to go to the next stage in the workflow.” The possibilities for automatic repair of faulty files range from simple to complex, depending on file format and workflow. Artwork Systems’ Enfocus group specializes in this technology, and claims to make it possible for professionals to preflight more than 150 file attributes and automatically correct the majority of them as part of the preflight pass with its PitStop Profiles or Action Lists. Enfocus technology can identify and automatically fix fairly basic problems—like improperly named spot colors—to more advanced issues, such as overprint settings. Enfocus also offers the technology in stand-alone products, such as PitStop Professional.

DALiM’s Ranasinha explains that, in fact, “Some file problems are (really) file optimization fixes that can be conducted during the preflighting process. In other words, there are ways a preflighting program could also create a more efficient file for the RIP. You have to bear in mind that all preflighting is not the same.”

The pitfalls involved in modifying PDF files are numerous and dangerous, Rosen adds. “To do what appears to be a simple correction from RGB to CMYK may produce a color change that would otherwise be fine if done on the native file. PDF was meant to be a final representation of what to print and how to print—not a file that should be edited, changed, and manipulated.”

Going Soft

Some preflighting software can reliably flag file errors by “soft-interpreting” the file, similar to the way a RIP does. According to Ranasinha, this is the only way deeper file errors can be weeded out. “Say the fonts are there but the data is bad. Lesser preflighting tools will ‘see’ that fonts are in the file, but won’t know that one is corrupted. Images may be seen as the correct resolution and/or color space, but might not open when they’re RIPped. Ink coverage is another example. If you print 330 percent max on your press, and some funky Photoshop file has been made with 350 percent total coverage, there is no way to extract that information just by looking at file header information.

Dalim Software applications are among the few systems that preflight files in this “soft-interpretation” fashion. Dalim’s Printempo software, for example, provides an intuitive drag-and-drop interface for online file submission by clients. After the Dalim Software applications preflight the files that have been received using their “soft-interpretation” technology, a low-resolution PDF File Preflight Report is generated. Any file elements failing the preflight are clearly highlighted on the file itself, making error detection and subsequent correction fast, easy, and above all, early.

Can’t be too careful

Preflighting is usefully performed on native files at any stage and in any area of the workflow. The software looks for color space discrepancies, inappropriate use of Pantone or specialty colors, unembedded or incompatible fonts, resolution conflicts, and problems with images, fonts, bleeds, etc.

Markzware’s FlightCheck Professional, for example, uses a simple drag-and-drop interface to scan a wide variety of file types, including InDesign, QuarkXPress, PageMaker, Multi-Ad Creator, Illustrator, Photoshop, FreeHand, and CorelDRAW, as well as PDF and other formats. After verification, FlightCheck Professional generates a detailed report, indicating whether the file has passed or failed the preflight tests, and spelling out specific problems that must be addressed before the file is ready to print.

“Like any assembly process, quality assurance should happen at various stages,” Markzware’s Rosen says. “Maybe a job arrived that is up to spec, but became corrupted when being moved from one location to another. Or a job arrives and appears to be valid, but for scheduling reasons needs to be processed on a different device or printed on a different press. By doing a final check, any issues can be caught before committing the job to plate or film.”

Every time a native design file is imported into an application it presents an opportunity for error. This is where PDF-based workflows shine. The use of PDFs dramatically reduces the time and labor associated with preflighting. And, because fewer variables are associated with PDF files, the results are more predictable. Because PDF saves documents exactly as they are intended to look, fewer questions arise about document design and page elements, rendering the entire process more efficient. According to Tyler Harrell, product implementation manager, Esko-Graphics, “It all could be the same file. The design file could even be the PDF file, especially in today’s environment. The workflow is streamlined if all files are the same.”

PDF preferred

But it is during the preflighting of the final PDF file used for output where the rubber meets the road. Explains Erik Cullins, director of sales and marketing, North America, Enfocus, “Native file preflight is useful when building a document to predict the quality of the final file; PDF preflight generally is used to determine final output quality” by making sure that both the elements of a graphics file and the file itself meet the specifications for the designated printing process.

Adds Gee Ranasinha of DALiM Software, “The design file is typically the native file, unless you ask it to create a PDF. The more important question is: Why are you preflighting? If you are preflighting for print output, what is the point to preflight the native file? You are not outputting a plate from that file. Whatever the file is that you output from—the last file before you RIP—that’s what you preflight.”

No can do

While preflighting may be something of a modern graphic arts miracle, it’s far from a panacea for everything that can go wrong with a file. Consequently, Rosen says, “preflighting as it stands today is not designed to resolve subjective issues that arise during the production of a print job,” nor to compensate for a lack of creative intelligence behind a given design.

For example, Rosen says, it may or may not be a preflight error when a box is positioned half on and half off the page, or when a job may print well but still be unacceptable to the print buyer. In other cases, the press may be slightly out of calibration or an ink nozzle is malfunctioning. Each of these, Rosen says, is beyond the power of preflighting to resolve.

Adds Cullin, “Many of the issues that preflight cannot resolve are design-specific. For example, while hairlines and small type can be fixed, a low-resolution image cannot be improved in any workflow.”

“Preflighting is not content-oriented,” states Esko-Graphics’ Harrell. For example, “There’s no way you can preflight marketing and legal copy.”

When it comes to objective print specifications, however, there is very little that preflighting cannot accomplish, he maintains, “even apparently difficult issues like verifying color space and barcoding.”

Miracles notwithstanding, says Ranasinha, “Unless a missing or corrupted font is available and resubmitted, we cannot make something out of nothing.”

Packaging variables

Packaging workflows present a few special preflight challenges. For example, packaging may introduce objective parameters such as page or job dimensions, die or cut lines, special trapping requirements, and more spot colors than usual. Other special considerations might include channel mapping, knockouts, or overprints. In a typical packaging environment, there are also many color models using non-traditional process printing.

However, while there are many applications that can determine what does and does not conform, automatic file repair is much more difficult in the packaging world because so much of packaging is comprised of graphic elements rather than text. According to Markzware’s Rosen, font sizes are a particular concern. In flexographic packaging, for example, “you often do not want reverse type smaller than six points. It would be dangerous to have a program that automatically increased text from three to six points because it might run over another graphic element or worse, legal copy.”

Furthermore, in packaging workflows, “Locations are completely customized, almost to an individual file,” says Esko’s Harrell. “There is no standardization, as in offset files, where so many pages are 7x 10˝, or 8.5x11˝. In flexo, there are an infinite number of structural designs to which the graphics have to conform.”

Finally, says Cullins, “If not created correctly by the designer, many of the special effects (blends and transparency options) used in packaging may require manual work at the production stage.”

Flexo versus offset

While you would identify errors in a flexo file in just the same way as you would identify them in an offset file, there are also different output standards when it comes to preflighting for flexo and offset. Says Harrell, “Typically there are more parameters or rules on a flexo file. For instance, if I had a limitation to text size in offset, it would certainly be lower than flexo. In flexo, CMYK copy lower than 10-point type would be considered unreadable. Even if there are limitations in offset, it’s much less severe. In flexo, you typically accept more spot colors than in offset. And, because of limitations in flexo plates, there is a restriction to the minimum line weight. That’s not a problem in offset.”

According to Vicki Blake, director of business development, Enfocus, and executive director, Ghent PDF Workgroup (GWG), The Ghent PDF Workgroup has defined four preflight profiles: one for exchange of design files to brand owner or prepress and three more for the exchange of files from prepress to converter, engraver, or flexo platemaker. Each addresses the specifics of the “downstream” printing process. These profiles are available free at www.gwg.org.

By the numbers

While the responsibility for preflighting files traditionally is said to lie with prepress, the truth is that the further upstream the preflight process occurs, the better the result will be. This places at least responsibility for the health and well-being of digital files at least partially in the customer’s lap.

“If a customer relies too heavily on a downstream partner to check the files for print-readiness, they run the risk of having files rejected or printing incorrectly. By moving file checking and repair upstream, the whole process is streamlined—and more time and money can be saved,” Cullins explains.

Customers also should have a set of ground controls or preflight preferences that they have received from the packaging provider before starting the job. “This will help them to preflight their job before outputting and sending the job to the printer,” Rosen says.

Communication between printer and designer is also key. “The printer should make any specific requirements available to the designers up front. Whether the designers choose to adhere to these job specs is up to them, but at least at this point, traditional prepress and the designers will have a common basis to discuss any problems that arise.”

Harrell agrees. “The designer should have the set of parameters to conform to. If the designer knows the rules, the file is built to the rules, and no file repair is needed. Esko’s DeskPack plug-in for Illustrator allows a converter to set printing parameters, create user names, and provide password protections to ensure the parameters are not tampered with. The designer loads the parameters and runs a utility to make sure the file conforms. The designer does his own preflighting, which saves time and money. You’re assured that clean files are sent to the converter. Prepress doesn’t have to redo anything.”

Best for packaging? That depends

Preflighting applications may be chosen for desktop, server-based, or a stand alone configuration, depending on the printer’s requirements and the print discipline involved. The client-server approach works especially well when an unlimited number of clients are accessing and processing files—all to the same file output and preflight characteristics. In contrast, there are ways for the customer to create incorrect settings with a stand-alone product. Typically, a server-based application is used to preflight large or complex files when they are received, and then using a desktop application for those that require manual correction.

Some options

Markzware’s Flightcheck is one of the oldest solutions for preflighting native files outside the original software, including PDF. Preflight tools designed exclusively for PDF production workflows include Enfocus Software’s Instant PDF, StatusCheck, and Pitstop Professional; Callas Software’s pdfInspecktor2; Apago’s PDF/X Checkup; Kodak Synapse Prepare; DALiM Software’s SWiNG; and Jaws PDF Courier from Global Graphics. Because the preflighting of incoming PDF jobs is a necessary task in modern packaging workflows, Esko-Graphics integrates the most common preflight tools in its comprehensive packaging and commercial print workflow, Scope. n