Talking about PDF/A and PDF/X, or other specific PDF standards, means talking about two different worlds: Information Technology (IT) and Graphic Arts (GA). These two worlds are tightly connected in most document management environments but were created using different approaches.
For 30 years, IT has supplied the GA world with digital technology in graphic reproduction: the first colour electronic prepress system (CEPS) was introduced in 1979 in Milan, Italy, and started a revolution in GA technology . The digital IT world has therefore existed for a few decades, but GA document management has centuries of history: the Gutenberg Bible is dated 1455. This is the reason why it is very hard for IT people to understand the GA methods for designing documents: the centuries of graphic design have left their mark on the language, working patterns and printing technology.
Basically, GA people search for reliability in a digital file. Reliability is the opposite of flexibility. For example, a PostScript file gives a lot of flexibility but only a medium level of reliability, whereas a CopyDot file presents the maximum of reliability but is difficult to handle. In the GA world, PDF is the balance between reliability and flexibility.
Today, the GA approach is influenced by people who work with analogue technology (films, analogue plates, torque…): this is the reason why the current PDF technology is not used by 100% of GA companies. Although standards like PDF are widely used, specific standards like PDF/X are not applied as often as managers and IT personnel would like. Fortunately, the scenario is changing very quickly with new generations of graphic artists who start their profession as digital natives. The use of proprietary file formats by specific composing software is declining compared to the use of specific PDF files: only complex graphic productions (ex. some packaging) are not yet covered by PDF ISO standards.
GA documents are created with a specific printing device or printing process in mind and contain elements that must be reproduced in the same way as designed on the original software. Operations like reflow, font substitution and change of resolution are not desired or not possible in most GA documents.
The first PDF/X standard (PDF/X-1a) was referred to as “digital film”: meaning that the document contained exactly the same content that user expected to see after the printing process (after impressing the analogue film). The other PDF/X versions that ISO TC130 defined (-3, -4…) contain certain information that need to be interpreted by the printing process workflow, like colour management, levels or transparencies, external references etc. This approach could be called “shared responsibility”
It is very important to consider this double approach (“digital film” vs. “shared responsibility”) when we talk about archiving or handling GA PDF documents. In most cases, GA digital data can be converted to PDF/X-1a. This is the scenario that can enable us to implement both the PDF/X and PDF/A standards. But new composing software produces content that can only be correctly exported in PDF/X-4; in this case it is very difficult to implement both the PDF/X and PDF/A standards today: we must wait for the PDF/A-2 file format. The other specific PDF formats like PDF/VT or PDF/E could also have an important role in some companies.
PDF/VT represents variable data printings, i.e. when a layout is fixed and the text changes every page (e.g. invoices). PDF/VT is strictly derived from PDF/X-4, and it therefore has the same limitations for PDF/A as mentioned above, until PDF/A-2 is released.
PDF/E is totally ignored by GA people, even though we hope to find in the future, and especially in the architectural world, mixed competences in companies (repro houses and copy services) that print and archive this form of document. Architectural projects are examples of an environment where the documents used require features of PDF/E for sizes, PDF/X for content presentation features and PDF/A for archiving purposes.
A typical GA workflow generates PDF directly from the applications or through a conversion of PostScript files. In the past, not all applications were able to correctly generate PDF files, and this is one of the reasons why some old GA people are suspicious of PDF. If we analyse the archive of a prepress company, we’ll find a lot of documents where the text is converted into vectors (high reliability, low flexibility). In this case it’s very hard to produce PDF/A-1b files with a minimum of text content. Automatic indexing and other features cannot be created.
Today we must accept having PDF/A-1b compliance files in the GA industry because they can be integrated with specific metadata to summarize the content: PDF/A-1a is not useful for the conversion of GA documents.
What are we expecting for the future?
PDF/A is supporting more and more features, and PDF/X potentially could be used for modern, cross-media production. A vision could be a company that produces content in both ways, to have the strongest graphic appearance and reliability and the strongest long-term archiving features.
 The development of international graphic arts standardization forum – Beijing September 2009 – proceedings – D. McDowell