PDF And You

Acrobat and PDF are starting to fulfill their prepress potential. Find out how to make them work for you.

Unless you've been stranded on a remote Pacific atoll, there's virtually no way you could have avoided hearing about Acrobat and PDF (Portable Document Format). Not only has Adobe churned out numerous news releases, but other vendors are jumping on the bandwagon, as well—and with good reason: This application and its derivative file format are now coming of age.

To recognize Adobe for its efforts to develop and promote PDF, In-Plant Graphics is honoring the San Jose, Calif.-based company with the 1999 Industry Leader of the Year award.

One thing that is just now becoming apparent to many people is the relationship between PostScript and PDF:

• PostScript is a page description programming language, also called an imaging model.

• PDF is a file format that relies on PostScript for imaging.

This is a critical distinction, as some people thought that PostScript would "go away" once PDF took hold. On the contrary, PostScript will stay right where it was always intended to be: in the background, acting as an interface between the digital design and its presentation on paper, film, plate or screen. What is more likely to disappear is EPS—encapsulated PostScript.

The third part of the puzzle is Extreme, which is Adobe's emerging architecture for high-performance printing using multiple processors and multithreaded OSs. By definition, a PostScript Extreme workflow requires PDF files as the means of exchanging content, the Portable Job Ticket Format (PJTF) to automate tasks in the workflow, and Extreme, which consists of the processing modules—including a RIP—and the framework for moving files from input to final output.

Meanwhile, Back In San Jose...

Acrobat is Adobe's application for creating, cataloging, viewing, modifying and outputting PDFs. As with previous versions, it is segmented into different applets, including Catalog, Distiller, Exchange and Reader. The last applet can be downloaded for free, but offers limited functionality; if your organization is going to work with PDF, install the full Acrobat.

With the new version, Adobe has made a number of improvements in Acrobat for working with office documents, including the ability to directly save out PDFs from office applications such as Microsoft Word. Another useful capability in the new release is the support for document scanners, so that legacy paper documents can be digitized and saved as PDFs. It can even convert HTML files directly into PDFs, though that is probably not something you should do prior to printing.

The interface has been completely redesigned, and now features a vertical toolbar. More important, though, Adobe has reengineered the Distiller configuration process so that it no longer resembles a Byzantine labyrinth. Whereas the previous version of Distiller required users to deal with 31 dialog boxes to correctly prepare a file for printing, Acrobat 4.0 is remarkably simple: there are three default settings from which to choose—ScreenOptimized, PrintOptimized and PressOptimized output. In addition, users can configure their own settings.

• ScreenOptimized output assumes that the document will be distributed electronically and printed only on low-resolution printers as a supporting tool. It converts all colors to RGB and downsamples images to 72 dpi to minimize transfer/download times.

• PrintOptimized is for content proofing. It is configured for 300-dpi output and maintains color settings, but lacks the refined settings required for high-end output. PrintOptimized would fit in well in a DocuTech/ DocuColor environment where color accuracy is not paramount.

• PressOptimized, the highest quality setting, assumes that the final output will be to an imagesetter or platesetter at typical resolutions in the range of ±1,200 dpi to 2,540 dpi. Here the full range of controls, including embedded fonts, halftone preservation, overprint, spot colors, and other settings are all included. These settings should be tested with your RIP and plotter to ensure that you get the desired results.

As for PDF, this is an object-oriented file format that is platform independent and can pass through Internet and intranet gateways with minimal risk of getting corrupted. Both of these are key benefits in the in-plant environment, where it is very likely that the marketing department is running on the Wintel platform, IT is on UNIX and the in-plant is running on the Macintosh, and where electronic file transfer is imperative.

Unlike PostScript, which requires interpretation (parsing), PDF files are already interpreted and require only declaration. That is, the text, image and graphic elements have been described as objects, but still need to be formatted for final output in terms of page geometry, resolution, screening and color. That is why, despite the fact that a file must be "distilled" into PDF, it still requires a RIP for final output.

The PDF specification is now at v1.3. Contrary to the carping of graphic arts professionals, it can handle color work. With plug-ins and a little extra work it can even generate spot colors. In fact, the current specification is a minor revision; the real improvements came with v1.2, which added all of the controls necessary for high-end printing, including process and spot color printing, OPI, UCR/GCR, overprints, and other neat stuff.

Among the features that have been added in the 1.3 specification are tools and/or support for trapping, embedding ICC profiles, trim and bleed, spot and special colors, and the ability to embed external data streams within the PDF. However, although the specification supports all of these capabilities, the stand-alone Acrobat 4.0 application does not, as Adobe has opted to rely on third-party plug-ins for high-end output controls.

In fact, the key to making PDF workflows work is to assemble a tool kit of plug-ins from vendors such as Acquired Knowledge, callas, Enfocus, Extensis, Lantana Research, Markzware, OneVision and Quite. Plug-ins do everything from automate the distillation process to managing color separations on the output device.

For example, Acquired Knowledge, callas, and Extensis all offer tools to manage the distilling process so that the content creator can print directly from the application. This is a major benefit for lean organizations that expect their marketing professionals to create their own promotional materials, as it enables the in-plant to transparently control the process.

Preflighting Still Required

Once the in-plant receives a PDF, it still requires preflighting and massaging before going out to an imagesetter or platesetter. Enfocus PitStop 4.0 now comes with its CheckUp preflighting tool to streamline processing, or try callas pdfInspektor; both give a complete rundown of what is inside the PDF. Just because it's a PDF doesn't mean it will output correctly, as not all RIPs can rasterize TrueType fonts, and graphics may be saved in the wrong color space or lack sufficient resolution.

Although it's possible to edit text in Acrobat, don't do it if there's a deadline looming—it's painfully slow and limited in functionality. Better to use an application like PitStop or OneVision DigiScript, which offer robust tools for editing text along with graphics and images.

Adobe has improved the graphics and image editing capabilities of Acrobat by integrating version 4.0 with Illustrator and Photoshop. These applications are automatically launched when the item is double clicked; once editing is complete, the graphic or image is saved back into the PDF. Another useful tool for editing PDFs is Macromedia FreeHand. For this to work, you will need a fast box (ie, 350MHz G3) and plenty of RAM.

Color Management

On the color management front, Adobe has announced support for ICC color profiles in rev 4, but this is a tricky issue for several reasons. First, PostScript doesn't support ICC profiles, so they must be embedded or attached in a PJTF using a plug-in. Further, the ICC profile support only covers the source color space conversion, not the output color rendering intent associated with the RIP's color rendering dictionary (CRD). Therefore, you must link these to produce accurate color—and complete the color-management loop.

For trapping, Acrobat 4.0 attaches the trap specifications to the PJTF file. Currently only Agfa has a plug-in that supports this feature. For Quark users, it's vital to remember that XPress only supports trapping when saved out as separated PostScript, which is distinctly at odds with a composite PDF workflow.

On the output side, useful tools include Lantana Crackerjack, OPI Doctor, and Quite Imposing Plus. Crackerjack is a utility that streamlines the process of making color separations from composite PDF files and is vital if you are working with a PostScript Level 1 RIP—as well as any Level 2 RIP that doesn't support in-RIP separations or RIPs with insufficient memory.

Crackerjack also solves the problem of spot colors, duotones, tritones and other DeviceN operators for those shops that lack PostScript 3 RIPs. Otherwise, you must have Photoshop 5.0 in order to save these in composite format.

For shops using an OPI workflow, Acrobat 4.0 reportedly supports the OPI 2.0 specification as well as 1.3. On a practical level, Lantana's OPI Doctor is a utility that helps troubleshoot and repair "broken" links, swap low/high-res images, change resolution, as well as rotate/resize the image.

The final step prior to output is to impose pages for the press. While this was a major hassle with prior versions, PDF 1.3 supports an imaging area larger than the page size (up to 200x 200˝), through the MediaBox, TrimBox, BleedBox and ArtBox operators.

• MediaBox defines the area needed to output PDF for conventional stripping.

• TrimBox describes the page size.

• BleedBox for pages requiring bleed.

• ArtBox for partial-page PDFs that are placed inside other applications.

As for tools, Quite Imposing Plus is an application specifically designed for stripping native PDF pages. ScenicSoft Preps v3.5, the leading application in the PostScript arena, can take in PDF files, but it converts them to PostScript prior to imposition. PressWise 3.0 supports PDF and can mix pages with PostScript and EPS files in the same signature.

Changes: The Only Constant

Adobe has improved Acrobat's support for collaboration and revision while documents are working their way through production. For technical documentation, books and other long documents, it is now possible to use multiple numbering schema to separate chapters, sections, and text parts.

There are also a number of security features that can be used to make sure only the appropriate personnel can access the document, as the permissions list can be embedded in the PDF itself.

As with earlier versions, you can print background text items such as "Not for Public Release," "Draft" and "Confidential." And, in addition to "sticky notes," Acrobat 4.0 provides overstrike, underline and yellow highlighter tools to expedite collaboration and revisions of text. It also enables users to mark up pages on screen as they would on paper.

Finally, for documents that are ready for release, the Windows version comes with a Digital Signature tool that enables the appropriate person to attach an encrypted algorithm "signature."

Still Missing

At this point, the biggest missing piece in the PDF arena is a practical way to integrate PJTFs to automate the workflow. The specification for these is out, but only Agfa has built a job ticket editor for its Apogee system.

One of the nice things about using PJTFs is that they are separate and distinct form the file itself: One PJTF can be used for multiple jobs processed the same way; multiple PJTFs can be attached to a job that is going to be output several different ways. Similarly, by attaching trapping and color conversion tags to the PJTF, changes in the output requirements can be handled more efficiently, because the content file has not been altered. In these cases, all that is required is to edit the PJTF and resubmit the job.

Alex Hamilton is president of Computers & Communications Consulting Inc., a Philadelphia-based firm specializing in digital technologies for publishing and printing. He can be reached at (215) 247-3461 or via e-mail at: alexh@candcc.com.

What About Other Vendors?

While many Adobe PostScript 3 RIPs can take in native PDFs and RIP directly to an output device, what about the other vendors' systems?

Harlequin and its OEMs can process native PDF files, so long as they are using ScriptWorks 4.5. Rampage is sticking with its EPS-based workflow, in which PDF pages are saved out as composite EPS files (omitting TIFF and EPS) and then RIPed and, finally, imposed. PCC (Professional Computer Corp.) also accepts PDFs, RIPs them into a vector format, then converts it to a raster file for screening and final output.

Agfa has developed a modular system called Apogee that works with PDF from start to finish. Apogee comprises a specially configured version of Distiller called Normalizer, along with a Pilot, a RIP and PrintDrive.

Scitex's workflow uses PDF as an input and as a "wrapper" for sending files to clients for approval. Files are RIPed into Scitex CT/LW for processing, with the resultant raster data then placed inside a PDF for review.

Heidelberg Prepress uses a similar approach for its Delta workflow, in which the file is RIPed into a DeltaList for trapping, imposition and output.

The key to making PDF workflows work is to assemble a tool kit of plug-ins from other vendors. Plug-ins do everything from automate the distillation process to managing color separations on the output device.

Quick Look

• PDF is an object-oriented file format that relies on PostScript for imaging.

• PDF is platform independent and can pass through Internet gateways with minimal risk of getting corrupted.

• Acrobat is Adobe's application for creating, cataloging, viewing, modifying and outputting PDFs.

• Adobe has improved Acrobat for working with office documents.

• Legacy paper documents can be digitized and saved as PDFs.

• PDFs still require preflighting and massaging before going out to an imagesetter.

• Text editing in Acrobat is slow and limited in functionality.

• Acrobat version 4.0 is integrated with Illustrator and Photoshop.

by ALEX HAMILTON