PDF Vole

If you don't have a license for Adobe Acrobat you can review the internal structure of a PDF with the free utility PDF Vole, available for download at http://www.softsea.com/review/PDF-Vole.html . After extracting the contents of the zip file, click on the Java file named, 'pdfvole_20090208.jar' to run the program. You can open one file at a time with PDF Vole.

Unfortunately PDF Vole does not give you the ability to search through the contents of the internal structure.

If you're looking for highlights or redactions try checking the objects towards the bottom of the Object Reference Table menu. Look for one with a type listed as '/Annot'.

Demonstration of How to Find Redactions in PDF Files Using the Adobe Acrobat Preflight Tool

See the demonstration video posted to my YouTube channel:

This example set uses PDFs redacted with three different programs. While this approach may not find any kind of redaction made to a PDF, it will help you find redactions made with widely used techniques, and expedite the review of large document sets.

1. The first PDF contains redactions made with the tool used in Adobe Acrobat.

2. The second PDF has redactions made with the highlighting tool of PDF Viewer Plus.Text was highlighted in black and then the file was written to a new PDF.

3. The last PDF has redactions made in Nuance Power PDF.

4. Use the Preflight tool in the Print Production menu.If this menu is not visible look for it in the drop down menu underneath where it says 'Comment'.

5. On the Profiles tab in the PDF analysis section, select:'List page objects, grouped by type of object'. . . then click 'Analyze' at the bottom right

6. On the Results tab, look for 'Vector objects (filled)' in the tree.

7. You should see indications that there are black objects on particular pages. Click the 'Show' button on the right to be taken directly to the redaction.

8. In the second sample PDF, the redaction will not be found with the page object analysis.

9. It's on page 3 but no object is found on that page.

10. To find this redaction, go to the Options menu on the right and select:Browse Internal PDF Structure

11. In the windows that opens, we can find an annotation listed under the specific page number at Parent\Kids\Annots

12. We can search in the Find box on the top for a reference to:/S:Highlight. . . or perhaps:/S:Redact. . . and we'll find the exact page on which the redaction appears.

13. In the third example PDF, the redactions made with the Nuance Power PDF tool can be found using the page object analysis, as with the sample with Acrobat redactions.

Utility to Copy Highlighted Text to Comments

It is possible to highlight sections of a PDF without having the selected text added to comments that can be easily exported, as discussed in the Tip of the Night for March 1, 2019. In order for highlighted text to be added to comments, the option in Preferences in the Comments category, "Copy selected text into Highlight, Strikethrough, and Underline comment pop-ups" must be checked off.

Gilad D. has posted a script here which can be used to add highlighted text to comments. The batch version costs $60, but you can test out a free version. It will download as a file named, 'CopyTextsToHighlights-DEMO.jar'

The trial version will only process the first three highlights in any PDF.