Adobe PDF vs. Microsoft XPS

CHANGE MAY be good or it may be bad, but it is nearly always disruptive.

In a production workflow, that generally means that when procedures change, mistakes increase, resulting in heightened inspection vigilance. Ultimately, though, the goal is to complete the process better, faster or cheaper.

Such a change is about to occur in digital printing and prepress as the adoption rates of Windows Vista and Office Suite 2007 swell, because Vista and Office 2007 create and print files differently than other systems.

Microsoft’s new document standard is the XML Paper Specification (XPS), which, like Adobe’s PDF format, is supposed to create files that are viewable on any platform, regardless of where they were created. Whether you consider XPS a great improvement in quality when printing from the Windows platform or a challenge to the de facto PostScript/PDF (Portable Document Format) models used by service providers, you will undoubtedly be receiving XPS files in greater numbers. So you should understand what XPS is, recognize the files when you get them, and be able to output them.

In the Microsoft Office Suite 2007 for the Microsoft Windows Vista platform, Word, PowerPoint and Excel files can be saved as 2007 application files, backward compatible (able to be opened with earlier program versions) application files or in the new XPS format. The Windows 2007 files are not backward compatible unless you save them as such and the new XPS file format is not cross-platform compatible unless you buy a viewer (similar to Acrobat reader).

Taking Sides

The XPS format is specifically designed to work well in the Windows office market because it makes it easier to transfer files from computer to computer and printer to printer without worrying about fonts and graphic images. Sound like PDF? It should, because it offers many of the same benefits. But fans of XPS say it is better than PDF because the fonts are always embedded, the color space is larger, and it will be less expensive to implement (you don’t have to invest in PDF creation software because the creation will occur within Vista).

PDF advocates answer that a properly prepared PDF embeds fonts and graphics, it does not need a larger color space (16 bits/pixel are available in both XPS and PDF and that only determines the number of color gradations in a gamut, not the dynamic range), and a less expensive strategy for transferring files is not meaningful when there is limited ability to open or edit the files on popular computer platforms such as Apple’s Macintosh.

XPS is not just a file format; it is also a spool file format and a page description language (PDL) for printers, such as PostScript. That means laser printers and high-resolution RIPs for digital presses and computer-to-plate devices will come to market with an XPS interpretation. Global Graphics announced one at Graph Expo ’07. Like any first-generation technology, XPS comes with a lot of issues that need to be ironed out.

There is already some suspicion on both sides about possible cooperative solutions to potential problems. For example, some in the industry question why the 2007 Office Suite does not automatically install a “save to PDF” option. And there are early, unconfirmed reports about difficulty in sending PostScript Type 1 fonts through the Windows print architecture.

To help understand the issues involved, we need to understand the previous technologies and motivations for a new solution. At WinHEC (Windows Hardware Engineering Conference) in 2005, Microsoft announced that its next generation Windows Operating System (then called Metro, now Windows Vista) would feature a new document and print format that would be closely integrated with the new Vista OS. The new format is part of a wider integrated document strategy for the Windows platform, which some in the industry see as pitted squarely against Adobe, the PDF format and the Acrobat platform.

According to Microsoft, the resulting shift to XPS was driven by the need to evolve from an out-of-date GDI- (Graphic Display Interface) based printing path to a more modern one. Applications running on Windows versions up to XP and 2003 Server used GDI for drawing onto the screen and for printing. Designed more than 20 years ago, GDI was not a sharable document format and it has proven to be insufficient. It cannot, for example, support transparent objects, gradients or masked images. Sometimes these were converted into boxes that took a long time to print and printed as low-resolution graphics.

GDI is also restricted to transmitting data in RGB, which is a huge problem when printing directly or saving to PDF files. GDI does not support the CMYK space used on many color devices and offset presses. In addition, it does not support single black colorant used on monochrome devices, and it doesn’t allow spot colors (used in professional printing), device-independent colors (e.g., those based on ICC color profiles) or hi-fi and photo-ink device color spaces (used in many ink-jet devices).

Early comments I have received from some printers indicate that the new Office 2007 printing system does not take advantage of the new printing structure in Vista and still prints using GDI protocols, and, as in previous versions of Microsoft Office, transparencies and gradients are not printing well.

Adobe has announced the development of a new printer driver that should get around these issues, but should be used only when printing from Microsoft Office or similar GDI applications that support transparency. When printing from other applications, such as all Adobe, Corel and Quark layout and graphic arts applications, the original PostScript driver that ships with Vista should be used.

If EPS files within Microsoft Office are being used, the original PostScript driver should be employed, rather than the new driver. Windows allows more than one driver to reference the same printer.

Drafts of this article were submitted to the manufacturers, and all issues it contains were discussed with them. When asked about printing Type 1 fonts or about problems when exporting Type 1 fonts to XPS or PDF, Microsoft’s Adrian Ford, senior program manager for the company’s Documents and Printing Team, said that Microsoft “cannot reproduce the reported behavior, and having also checked with the Office team, we are not aware of any reported problems in this area.”

There is a downloadable plug-in that exports Office 2007 to PDF files, but there are reports that Type 1 fonts become low-resolution bitmapped fonts or changed (font substitution) when the Save to XPS or Save to PDF options are used. When I mentioned this to Ford, he said that the Type 1 fonts should be converted to Open Type fonts and become embedded. He added that neither the XPS team nor the Windows team is aware of any of these printing problems and referred me to his blog (http://blogs.msdn.com/adrianford) for more information about all things XPS.

“I’ve checked printing to PostScript from Word 2007 on Windows Vista and can confirm that the resulting PostScript contains the Type 1 font information for the Type 1 font referenced in Word—i.e. the font glyphs have not been rasterized,” testified Ford.

In the case of creating a PDF from the 2007 Microsoft Office System (aka Office 2007) using the Microsoft add-in, Ford suggested the following: “When saving a Word document that contains a Type 1 font as a PDF using the add-in, the resulting PDF usually contains the original font information, i.e., the font glyphs are not rasterized.

“The XPS format does not support Type 1 fonts directly; XPS only supports fonts in the OpenType format. Applications that create XPS, including the ‘Save as XPS’ add-in for Office 2007, need to convert from Type 1 to OpenType,” he added.

OpenType is a cross-platform font format developed by Adobe and Microsoft, and Ford suggested those who want a non-Microsoft source of information should visit www.adobe.com/type/opentype . He noted that “because the XPS format enforces font licensing flags, the ‘Save as XPS’ add-in for Office does not provide an option to override rasterization of glyphs. If a font is not licensed for embedding, then the glyphs are rasterized.” The only problem here is that Type 1 fonts do not use font licensing flags.

Since our initial conversation with Ford, we have received confirmed reports of Type 1 font problems in XPS and PDF files.

According to Shafath Syed, Adobe product manager for Electronic Publishing, one of the best ways to get XPS files into a PDF workflow may be to import them into Acrobat 8 on the Windows platform and export a PDF, then preflight and repair the PDF file (if necessary), using Acrobat 8 or other preflight programs such as Quite a Box of Tricks, Enforces Pit Stop, or the new Enforces Neo. After passing the preflight check or completing repairs, the PDF should print out correctly using the original PostScript driver in Vista.

Early Reports

It must be stressed that problems with XPS are early reports from just a few individuals and that each printer should determine how the Windows 2007 files and XPS files will print in his workflow. The following steps can help provide a clear picture of how the new files will work for you:

• Become familiar with the new extensions for the Windows 2007 Open Office XML new products.

• Upgrade one machine to Vista and 2007 Office Suite and create an XPS file (containing transparencies, gradients and Type 1 fonts). Print it and examine it.

• Print the test file from Windows 2007 directly to your PostScript device with the original PostScript driver. Print it and examine it.

• Ask the manufacturer of your PostScript device to inform you when Adobe ships the new printer driver. Once it is available, install it and repeat the last test.

• Install the tools for file conversion, such as Save to PDF, and repeat the test with the original PostScript driver. Open an XPS file with Acrobat 8 for Windows, save it to PDF, and repeat the test. IPG

Reprinted with permission from the NAPL Business Review (www.napl.org). © NAPL 2007.