How to Fix Missing Special Characters in Adobe Acrobat PDFs
Question details
Users need to resolve an issue where special characters fail to render or display correctly when viewing or editing PDFs.
- Product
- Adobe Acrobat / PDF
- Device & OS
- not provided
- Scenario
- Viewing a document or entering text containing special characters (like Greek letters or superscripts) into a PDF file or form field.
- Observed behavior
- Special characters like the Greek letter Sigma and superscripts do not appear, or appear as unreadable boxes and symbols.
Ensure you know which specific font was used to create the document and verify whether you are only viewing the PDF or actively typing into form fields.
Use and Embed a Supported Unicode Font
Ensure the font used in your PDF supports the required special characters and is fully embedded within the file.
Missing glyphs or unsupported characters are usually the result of non-embedded fonts or using a font that lacks the specific character mapping required for special symbols.
Choose a system font that contains a wide range of Unicode characters, such as Arial Unicode MS or a Noto font family, for your source document.
When exporting or printing to PDF from your source program, access the 'Properties' or 'Job Options' menu, navigate to the 'Fonts' tab, and check the box to 'Embed all fonts'.
If you are typing into a PDF form field in Acrobat, right-click the field, select 'Properties', go to the 'Appearance' tab, and change the font to a Unicode-compliant font.
Verify Acrobat Version and Input Method
Determine if the issue is specific to the version of Acrobat or the exact location where text is being entered.
View and Edit PDFs Seamlessly with WPS Office
Avoid font rendering issues and missing characters by using the built-in WPS PDF tool. WPS Office provides native support for rendering complex Unicode and special characters accurately.
- 1. Open your PDF in WPS: Launch WPS Office, click on 'Open' on the home screen, and select the PDF file that is missing special characters.
- 2. Access PDF Edit mode: Navigate to the 'Edit' tab at the top and click on 'Edit Text' to interact with the document's contents.
- 3. Apply a Unicode font: Highlight the text that is missing the characters, open the font dropdown menu on the ribbon, and select a comprehensive font like Arial.
- 4. Save and preserve fonts: Click 'Menu' > 'Save'. WPS PDF automatically manages font resources to maintain visual fidelity and character display.
Frequently Asked Questions
Why do special characters turn into boxes or question marks in my PDF?
This usually happens when the font used to create the text does not contain the specific glyphs for those special characters, or the font was not embedded correctly when the PDF was originally exported.
How do I know if my fonts are embedded in an Acrobat PDF?
You can check the font embedding status by opening the PDF in Adobe Acrobat, navigating to 'File' > 'Properties', and clicking on the 'Fonts' tab. This screen will display a list of all fonts used and indicate whether they are embedded.
Can I type special characters directly into a PDF form field?
Yes, as long as the form field's appearance properties are set to use a font that supports those special characters. If they appear blank or as squares, you must right-click the field, open its properties, and select a wider Unicode font.
