Compare PDF Files

Reporting all the modifications made to a document is a difficult task if changes weren’t tracked during the editing process. Comparing the new document with its original version is the easiest way to pinpoint every single change that was made. To compare two versions of the same document, convert them to PDF in Nitro Pro and use the Compare tool to identify any differences in text, images, and even annotations.

Show context changes

A context comparison searches through the objects on each page and checks if they exist on the second document. If an object exists, it is then compared for differences with its neighbor. Text, images, and annotations are compared during this process.

To compare content:

  1. Open the two documents that must be compared

  2. On the Review tab, in the Document panel, click Compare. The Compare Documents dialog appears.

  3. Select the Compare text-based documents option, and then click Next

  4. Use the Original Document and Changed Document menus to load each document accordingly

  5. Click Preferences to change the Compare tool settings. The default settings will cover the most common scenarios.

  6. Beneath the document previews, select the pages to be compared:

    • All: Compare the entire document
    • Current page: Compare only the page shown in the preview area
    • Pages: Enter the desired page or range of pages (separated by a dash). For example, to convert pages 3, 4, and 5 of an 8-page document, enter 3-5.
  7. Click OK to begin the comparison process

Understanding the results:

After the two documents are compared, a new tab will open in Nitro Pro’s Document Pane to illustrate the visual differences detected in the files. After a content comparison, the resultant file will highlight every difference based on the color coding that can be configured in Nitro Pro’s Preferences.

Show only differences

A visual comparison captures an image of each document and looks for differences at a pixel level. The result is then shown as an image containing only the differences between the two documents.

To compare visually:

  1. Open the two documents that must be compared

  2. On the Review tab, in the Document panel, click Compare. The Compare Documents dialog appears.

  3. Select the Compare scanned and image-based documents option, and then click Next

  4. Use the Original Document and Changed Document menus to load each document accordingly

  5. Click Preferences to change the Compare tool settings. The default settings will cover the most common scenarios.

  6. Beneath the document previews, select the pages to be compared:

    • All: Compare the entire document
    • Current page: Compare only the page shown in the preview area
    • Pages: Enter the desired page or range of pages (separated by a dash). For example, to convert pages 3, 4, and 5 of an 8-page document, enter 3-5.
  7. Click OK to begin the comparison process

Understanding the results:

After the two documents are compared, a new tab will open in Nitro Pro’s Document Pane to illustrate the differences detected in the files. After a visual comparison, the result will be an image file consisting of the delta pixels that were found to exist only in one of the files.