How to Fix Highlighted PDF Text Hidden by Opaque Yellow in Reader
Question details
The user needs to make scanned document text readable again after yellow highlight annotations appear opaque in certain PDF viewers.
- Product
- PDF Viewer (Acrobat Reader, Chrome)
- Device & OS
- not provided
- Scenario
- Opening a previously highlighted scanned PDF in Acrobat Reader or Google Chrome.
- Observed behavior
- The yellow highlight covers the text opaquely instead of being transparent, making the underlying text completely unreadable.
Ensure you have access to a full PDF editor to modify existing annotation properties, as basic PDF viewers only allow you to view the document without changing highlight opacity.
Reduce Highlight Opacity in PDF Properties
Adjust the appearance settings of your highlight annotations to make them transparent so the underlying text remains visible across all viewers.
In basic PDF viewers like Chrome, graphical highlight layers on scanned documents without OCR may fail to blend properly, causing them to render as solid opaque blocks. Adjusting the opacity directly in the PDF properties resolves this issue.
Open the affected PDF document in an advanced PDF editing application.
Right-click on the opaque yellow highlight that is covering your text and select 'Properties' from the context menu.
Navigate to the 'Appearance' tab in the Properties dialog. Locate the 'Opacity' slider or percentage box and reduce it to about 20% to 30%.
Click 'OK' to apply the changes. Save a new copy of the PDF and open it in Acrobat Reader or Google Chrome to verify the text is now readable.
Use WPS Office to Highlight Scanned PDFs Reliably
WPS Office offers an advanced built-in PDF editor equipped with smart annotation tools. It automatically adjusts highlight blending to ensure your text remains visible, preventing opaque layer issues when viewing the PDF in web browsers or standard readers.
- 1. Open the PDF in WPS Office: Launch WPS Office, click on 'Open', and select your scanned PDF document.
- 2. Select the Highlight Tool: Go to the 'Comment' tab located on the top ribbon and click on the 'Highlight' icon.
- 3. Highlight Your Text: Drag your cursor over the scanned text. WPS Office handles the blend mode automatically so it remains transparent.
- 4. Save Your Document: Click 'Save' to ensure the transparent highlight is properly embedded for any PDF viewer.
Frequently Asked Questions
Why do highlights look fine in my editor but completely opaque in Google Chrome?
Google Chrome's built-in PDF viewer uses a simpler rendering engine than full PDF editors. It sometimes ignores complex 'Multiply' blend modes used by highlights, rendering them as standard graphical shapes which appear fully opaque.
How can I prevent this issue on scanned documents?
Performing OCR (Optical Character Recognition) on your scanned PDF before highlighting solves this. Once the software recognizes the image as actual text, the standard text-highlighting tool attaches to the words instead of drawing an overlay box.
Can I change the opacity of all highlights at once?
Yes. In your PDF editor, open the Comments pane, select all highlight annotations (usually by holding Shift or Ctrl), right-click to open Properties, and change the opacity. This applies the new transparency level to all selected highlights simultaneously.
