Frequently Asked Questions
Q. What's this about PDF/X-1 and PDF/X-2?
Bailey: The original intent of the standard was that it be split into two. PDF/X-1 is a file format for what's known as "blind exchange," where all technical information and content is held within one single file and nothing needs to be supplied alongside it, while PDF/X-2 will be a format for more open exchanges.
PDF/X-2 will address exchanges where there is more discussion between the supplier and the receiver of the file. The receiver may have certain fonts available which would therefore not need embedding, or maybe the receiver already holds high-resolution images to replace proxy images (low-resolution previews) in the supplied line.
PDF/X-1 is limited to colors defined in CMYK (and posts) only. PDF/X-2 will also allow device-independent color spaces, like Lab, to be used.
Q. Isn't PDF/X raster-only? It's just a wrapper for TIFF/IT, isn't it?
Bailey: Although it's possible to use PDF/X-1 as a wrapper for TIFF/IT files, that is not the intent of the design. A PDF/X file can—and usually will—include vector objects (such as rules, fills and text) using normal PDF constructs. It can also include image data, whether scanned or computer-generated. In this sense, PDF/X is very similar to both PostScript and PDF. Unlike PostScript, PDF/X-1 can make references to TIFF, EPS, DCS and TIFF/IT-P1 files and actually have external files embedded within it (although PDF/X-1a, PDF/X-2 and PDF/X-3 cannot).
Q. Where can I get more information?
Bailey: CGATS information is available at the Web site for NPES, The Association for Suppliers of Printing, Publishing and Converting Technologies: www.npes.org/standards/cgats.htm.
The DDAP Web site maintains a list of software either already available or being developed to support the PDF/X standards.