Hamilton--The Great Schema of Things

It is increasingly difficult to find major vendors that have not jumped onto the XML bandwagon. Adobe, Agfa, Heidelberg and MAN Roland have teamed up to develop the Job Definition Format (JDF) using XML, while CreoScitex and Quark are both building XML-based applications to drive their own systems. In the e-commerce space, printCafe, PrintTalk—a nascent group of firms—and others are building transaction and supply chain management systems based on eXtensible Markup Language.

Not to be left out, the on-demand group PODI has published a specification called PPML—Personalized Print Markup Language—based on this spec, and still another industry initiative, called the Internet Printing Protocol (IPP), is using XML constructs to enable remote printing using the Internet. If it sounds a little confusing, that's because, at this point, it is.

Even worse, I'm one of the people who's helping spread the messages. I believe that XML could be the Holy Grail of metadata. Whereas PostScript and HTML are descriptive languages that specify how a print or Web page looks in terms of things such as fonts, graphics and layout, XML goes deeper, as it provides the means of explaining what the text or graphic is about.

XML also provides for formatting through the eXtensible Stylesheet Language (XSL) that can be used to drive layout/composition tools such as Quark-XPress, PageMill and other applications. Using XML and XSL, not only will we know what the content is, we'll know how it should look for each type of media in/on which it is published. Nirvana, here we come.

What's important about all these initiatives is that they are not necessarily competitive. For example, JDF is intended to define an architecture that will completely automate print production by enabling multiple parties and systems to communicate with one another using the Internet.

From the time the client requests a quote through the time the job leaves the shipping dock on pallets, JDF will integrate every step so that files never get to the RIP without having passed a preflight; each press always gets plates imposed specifically to suit its requirements; and bindery lines are set up and operated at maximum capacity.

Although its PCX is a proprietary effort, the printCafe group has such a large installed base in printers' business management systems that it cannot be ignored. If I understand things correctly, PCX will complement JDF in terms of providing workflow automation tools further upstream—content creation—and with transactions between printers and their suppliers. The word is that we will see a working iteration of PCX at Graph Expo next month.

PODI's PPML is focused tightly around building a single set of rules, if you will, that will make it possible to print variable-data documents on any digital printing system, whether it be an Indigo, Xeikon, Xerox or one of the new Nexpress systems developed by Heidelberg and Kodak.

As far as I can tell, IPP is an attempt to define a specification to enable the distribute-then-print model at an individual level within the enterprise. While this may eventually have serious ramifications for commercial printers, it's not even on the radar screen at this point.

Now for the bad news. Although XML can do all those wonderful things and many more, it requires what is known as a Document Type Definition (DTD) or schema to drive a computer-integrated manufacturing system. This is where the devil lies in the details.

Like any language, the value is proportional to the number of people who understand it. And DTDs are the dictionaries, if you will, that enable people and systems to understand what is meant by the XML constructs so they can interpret and process the actual data files. And while DTDs are in the public domain, residing somewhere within the server bowels of the World Wide Web Consortium, they still must be written and maintained, and the new ones must jive with existing ones.

Right now, the JDF spec is being written and PCX is under construction; the PPML spec is published and a number of vendors have pledged to support it, but it, too, is still a "futures."

Another issue that must be addressed is how all of these specs will integrate with the CIP3 Print Production Format (PPF) specification that has been in the works for more than five years. Although this is not a political issue, there's a lot of leg work that has to be done in order to make everything work together.

Thus early adopters of XML will most likely find the road filled with potholes, or, more accurately, not yet paved. Writing the DTDs is a time-consuming task that will generate the same sort of approval from publishing, prepress and printing company managers as training: Just do it, without asking for money or time. Furthermore, since publishing and printing is inherently a multi-party process, it is critical that the DTDs be publicly validated by bodies such as the Graphic Communications Association (GCA), which have been working on EDI initiatives for some time.

Now, the "buzz" is circulating, but the time when software that takes advantage of these applications is available for public consumption is in the future. How far in the future is anyone's guess, but you can be reasonably sure you'll probably have a hangover by then.

—Alex Hamilton

About the Author
Alex Hamilton, a former technical editor with Printing Impressions, is president of Computers & Communications Consulting, which specializes in digital technologies for printing and publishing. He can be reached at (215) 247-3461 or by e-mail at alexh@candcc.com.