The biggest obstacle between publishers, printers and agencies involves digital file formats. When an agency submits a file that is unacceptable by a publisher, the end results may be less than satisfactory for the printer. And while at first, the differences between TIFF, JPEG and PDF may seem subtle, each format offers highly specific benefits throughout the production process. And though one party may champion the use of PDF, another may realize that the Adobe-branded format actually consists of many versions, such as PDF-X, PDF-X-1 and even PDF/X-1a. To alleviate much of this confusion, below is a list of commonly used formats and their basic attributes. For more practical information on this topic, read Linda Manes Goodwin's ongoing column in PrintMedia magazine, "Digital Directions," where she discusses formats on case by case studies. Please also note that many of her insights are archived online.
GIF (Graphics Interchange Format) uses approximately 256 colors within the average desktop monitor spectrum. File compression is also available for smaller files requiring faster downloads. This format is best suited for images with solid colors or consistent color, including brand logos and line art.
JPEG (Joint Photographic Experts Group) is used for digital photography. Unlike GIFs, JPEGs reproduce using the full spectrum of desktop colors. But similar to GIF, JPEG can be compressed for faster download, though its compression discards data in the process.
TIFF (Tagged-Image File Format) is used most commonly for bitmaps, but is supported by virtually all graphics applications. It's a commonly used file among publishers between editorial, production and art departments.
EPS (Encapsulated PostScript) is used for both vector graphics and bitmaps. Unlike GIF and JPEG, EPS files also contain PostScript descriptions of enclosed data.
PDF (Adobe Portable Document Format) is widely used for online publishing. Its small size greatly reduces download time, thus making it efficient to deliver text, image and entire documents within one file. Also, it is platform independent (working with both PC and MAC platforms) and Acrobat, the software used to read PDF files, is free from Adobe. Because it is Adobe-based, the format is also PostScripted with embedded fonts that contain hyperlinks and are fully searchable using Web browsers.
PDF/X, though related to PDF, is a hybrid designed specifically for prepress file exchange. Whereas PDF formats offer many of these same advantages, they are not always best-suited for graphic arts environments. Instead, PDF/X outputs higher-quality files, fast becoming the preferred format among graphic designers and advertising agencies.
PDF/X-1 contains both content and technical information within a single file. For instance, publishers outlining ad acceptance standards to agencies and prepress houses do not need additional technical data for file delivery. But the ANSI/CGATS standard is limited to colors defined in CMYK spaces only. Additionally, PDF/X-1a, a division of PDF/X-1, and automatically embeds files with TIFF, TIFF/IT, EPS or DCS files.
PDF/X-2 is designed for exchanges between suppliers and receivers of files, in a case where a file receiver doesn't require embedded fonts or already stores high-resolution images with low-resolution previews. PDF/X-2 also supports device-independent color spaces.
For more information on digital file standards, visit the following Web sites: