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• Posted Nov. 16, 2012, 8:49 a.m. - 11 years, 11 months ago

What is PDF/A and When Should You Use It?

PDF/A is a standard that allows for very long-term archiving of PDF files.  You may be wondering why a normal PDF would not be suitable for extremely log-term archives.  We will explain.

 

 

Do you happen to have any vinyl records?  How about an 33-1/3 RPM LP records?  With the CD being the most popular physical media for music, it is hard to find a record player for the older vinyl records.  Even harder to play are the old original Edison cylinders music recordings.

If you remember the 8-Track cartridges with their players installed in automobiles and happen to have a stack of those cartridges, try finding a player in good condition that will not shred the tape inside!  You get the idea: PDF files that exist today may not be readable years into the future.

The PDF/A-1, PDF/A-2 and PDF/A-3 standards guarantee that PDF files will be readable in the future.  A PDF that has a URL link to an external web site or external document is not good for long-term archiving.  You cannot be absolutely sure that the web site that is referenced in the document will even exist 10 or 20 years from now, let alone the web page referenced.

A PDF/A document must be entirely self-contained.  Take fonts for instance.  There are thousands available today, that may not be available tomorrow, so a PDF/A document has to have all fonts embedded.  In fact the embedded fonts must be able to be legally embedded for unlimited use indefinitely; many fonts today have licensing requirements and those cannot be used for long-term archiving.

JavaScripts as well as encryption is also forbidden.  I challenge you to find a decoder for the very first available encryption algorithm ever made public.

Embedded files are permissible in PDF/A-2 files (2011 standard) as well as JPEG2000 and LZW image compression.  PDF/A-3 (2012 standard) files allow for completely embedded files.

Most PDF programs allow for you to save in a PDF/A-1 format for archival purposes.  Support for the newer PFD/A-2 and PDF/A-3 standards may take some time to put into practice.  Check with your software vendor if you need the advanced functions and wish to remain compliant.

Archive photo via Flickr by ValleeC

 

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