Chapter 5. Pre-press

5.7 Preflight

Wayne Collins

We have covered quite a few parameters that must be considered when preparing a computer graphic for manufactured image reproduction. The parameters shift with different substrates and imaging technologies. The task of checking a computer graphic document in preparation for the manufacturing process is called preflight. Most graphics are created by designers who are working separately from the manufacturer. In some cases, preflight preparation is the responsibility of the designer, or graphics creator, and in some cases, it is the responsibility of the manufacturer. Some manufacturers charge extra if they have to correct a graphics file that is not prepared properly for their imaging process. Most do not charge extra for preflighting, trapping, or imposing a file for their imaging process. Problems occur when all parties believe a file is prepared properly, but it causes errors in the RIP process. A poor font, improper colour separations, and transparency settings that drop out layers on a page are problems that occur most often. This is when time, materials, and money are wasted, and critical media campaign deadlines are missed. Preflight tries to catch the problems before they reach the RIP.

Designers or graphics creators can purchase separate preflight software that will generate reports about a PDF or PostScript file before they submit it to a manufacturer. The most popular dedicated preflight software is from Markzware and is called FlightCheck. There are also a few other companies that are popular in the marketplace. Enfocus bundles its preflight software with a suite of PDF editing tools called Pitstop. The Adobe Creative Suite has preflight functions built into its software suite. Adobe InDesign is the page layout software of choice for creating multi-page documents such as brochures, pamphlets , or books. The preflight module in InDesign will generate a report that can be included with the packaged contents a designer should provide to a manufacturer. The report will list important information about the InDesign document, such as that found in the list below. Adobe Illustrator also has a built-in preflight tool, and Adobe Acrobat has preflight tools that designers should use to analyze their PDF files before submitting them to a RIP.

Various industries have set PDF standards. The magazine publishing industry, for example, developed a PDF/X standard to ensure PDF/X files can be written only if they meet a set of specifications that are common for lithographic magazine production. Other manufacturing processes adopted the standards if they were appropriate for their imaging technology and PDF workflows.
Most preflight software checks for the following elements in an electronic document:

  • File format
  • Colour management
  • Fonts
  • Spot colour handling
  • Page structure
  • Thin lines
  • Black overprint
  • Trapping