Comparing two PDF Files

A powerful feature of Adobe Acrobat (version 5.0 or version 6.0, 7.0, and 8.0 Professional) is the ability to compare two versions of a PDF document and create a third document with the differences highlighted.  Although this feature is probably not needed by most people on a day-to-day basis, when it is needed, it is great to have.

Consider a situation in which two different sets of construction documents have been created at different times (such as an early-release set and a final set) and it is necessary to determine what has changed between the two.  Doing this the old fashioned way is one of the most boring tasks imaginable, and you can never really be sure that you have checked everything.

As an example, two versions of a detail sheet are shown here:

Version 1

Version 2

Can you spot the four differences in these two files?  Here's how to automate this process with Acrobat:

• Under the Tools menu, choose Compare > Two Documents... 
• Select the two documents in the dialog box windows
• Choose Page by page visual differences and High sensitivity as the comparison options.  This will ensure the best possible comparison.
• Click OK. 

Acrobat will then create a new PDF file containing two header pages that summarize the comparison, and duplicates of the compared pages with differences highlighted inside magenta hexagons.  The comparison report generated from the examples above is shown here:

Comparison report

It may be necessary to zoom in on the duplicate pages to see the highlighted areas.

Note that the comparison feature is not included in Adobe Acrobat Standard.  It is included in version 5.0 of Acrobat, and in Acrobat Professional.

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