Fix Acrobat Compare Tool Not Detecting Text Changes in PDFs
Question details
The user needs to fix an issue where the document compare tool only detects page-level changes and image replacements instead of specific textual modifications.
- Product
- Adobe Acrobat 2017
- Device & OS
- not provided
- Scenario
- Comparing two PDF lease agreements to identify exact textual modifications.
- Observed behavior
- The comparison tool fails to recognize text changes, treating the documents as image replacements or page insertions even after applying OCR and adjusting scan settings.
Ensure neither of the PDF files is restricted by a permissions password, as editing and copying restrictions can block the comparison engine from analyzing the text layer.
Run OCR and Save as a New PDF
Rebuilding the text layer using Optical Character Recognition (OCR) ensures that the comparison engine can read and analyze the characters properly.
If the PDF contains outlined text or image-based content, standard text comparison will fail. Running a fresh OCR process and saving it as a completely new document forces the software to create an accessible text layer.
Open the problematic PDF file, navigate to the 'Tools' tab, and select the 'Scan & OCR' option.
Click on 'Recognize Text' in the top toolbar and choose 'In This File' to process the entire document.
Once the OCR process finishes, go to 'File' > 'Save As' and save the document under a new name to prevent overriding original data.
Repeat this exact process for the second lease agreement, then run the 'Compare Files' tool using your newly saved documents.
Recreate Documents from the Original Source
Exporting fresh PDFs directly from the source application resolves deep-seated encoding and corrupted text object issues.
Install the Latest Software Update
Updating the software applies patches to the comparison engine that address known bugs and compatibility limitations.
Compare PDF Text Seamlessly with WPS Office
If your current PDF tool struggles with detecting textual changes due to encoding or image errors, WPS Office offers a robust PDF editor with a highly accurate document comparison engine to easily identify additions, deletions, and modifications.
- 1. Open WPS PDF: Launch WPS Office and click on the 'PDF' tab to access the dedicated PDF workspace.
- 2. Select PDF Compare: Navigate to the 'Tools' menu on the top ribbon and click on the 'PDF Compare' feature.
- 3. Upload Documents: Add your original lease agreement and the modified version into the respective comparison upload fields.
- 4. Analyze Differences: Click the 'Compare' button to instantly process the documents and highlight all textual, structural, and formatting changes.
Frequently Asked Questions
Why does my PDF compare tool treat the entire page as an image instead of reading the text?
This occurs when the document's text has been converted to vector outlines, contains severe font encoding issues, or was created as a flat image scan. Because the software cannot isolate individual character data, it registers the whole page as a single image replacement.
How do I know if the text in my PDF lease agreement is outlined or image-based?
You can test this by using the standard text selection tool. Try to click and drag over a single word or sentence. If the entire page gets highlighted at once or you cannot select individual characters, the text is image-based and requires OCR to be editable.
Will enabling the 'Compare Text Only' setting fix compatibility issues in scanned PDFs?
Not inherently. The 'Compare Text Only' setting filters out formatting changes, but it still relies on a functional text layer. If the text layer is missing or damaged, even this specific mode will fail until you recreate the PDF or run a fresh OCR scan.
