PDF Standards

Best Practices for Optimizing PDF for High Speed Printing

Adobe Portable Document Format Overview

Portable Document Format (PDF) was originally created to help people exchange documents in a common format across different operating systems, independent of specific software. These documents could easily be shared and incorporate security features, so they could not be modified. 

The original intention of PDF was for viewing on a computer monitor. As their purpose expanded, PDFs began to be used for printing as well as viiewing. Depending on how the PDF file is prepared, printing can, and will, present some challenges.

PDF has evolved over the last 20+ years to better accommodate printing. There are still a few capabilities required in high volume printing and available through other Page Description Languages that are not available with PDF. Some of these capabilities include: 

1. Tray pulls are not available in PDF format
2. Selection in the PDF for front or back is not available
3. Selection in the PDF for simplex or duplex is not available
4. Font control

Some of these items can be overcome with Print Drivers and Custom Scripts.

Optimizing PDF for High Speed Printing

There are two main benefits that result from optimizing PDF file preparation for high
speed printing systems.

• Achieve optimal print quality
• Print at rated speed of printing system

Ensuring that the printer runs at rated speed is critical for capacity and SLA planning. A poorly constructed PDF file can significantly impact processing and print speed. An optimized PDF for printing will “rip” and print faster while giving you the highest print quality possible.

There are simple steps you can take to make a PDF “optimized” for high speed printing. Some of these best practices can optimize the PDF job right at the creation level just by selecting the ideal PDF output options.

Best Practices for Optimizing PDF

Here is a list of the “best practice” selections to get the fastest and highest
quality print output from your PDF.

Leverage CMYK format:

• CMYK (Cyan, Magenta, Yellow, Black) is what the Printers use to print and the front end is optimized to accept this input.
  • PDFs are often created using RGB which is how data is presented on a computer monitor.
  • When a PDF is prepared using RGB, the Printer Front End will convert the RGB to CMYK, which can have a negative effect on the processing and speed of print.
  • In addition, RGB to CMYK conversations can often affect print quality and color fidelity.

Use embedded fonts:

• If the fonts are not embedded in the PDF document, three scenarios can generally happen.
  • The job will not process.
  • The missing font will be looked for in the Windows font directory. This can cause delays in processing.
  • If the font is not found, a substitute font will be used. The substituted font will not be an exact match and can cause fidelity issues.

Optimize transparencies within the PDF:

• Transparencies create a significant processing requirement on the front end.
• The optimal format to ensure best combination of print quality and processing speed is the PDF Standard PDF/X-1a.
  • PDF/X-1a removes layers or transparencies, ensures fonts are embedded, and will convert all objects to CMYK (while retaining named spot colors).

Conform to the PDF/X Standard:

• PDF/X-1a is acceptable
• PDF/X-3 is acceptable
• Following either of these standard will provide the best path for optimal output fidelity and processing.

Use Black versus Rich Black:

• Rich black is an ink mixture of solid black over one or more of the other SMYK colors. It is often used when the "K" ink alone does not yield a dark enough black tone.
• Rich Black addes unnecessary cost to the application by using additional SMY ink.
• Black is generally described as 100% "K".
• Rich Black uses some combination of varying percentages of CMYK.