Fix Digital Signatures Appearing as Images in PDF from Excel
Question details
The user needs to fix an issue where applying a digital signature to a PDF document results in it rendering incorrectly as a flat image.
- Product
- Adobe Acrobat Reader DC, Microsoft Excel
- Device & OS
- Windows 10 Pro
- Scenario
- Signing a PDF document that was saved or exported directly from Microsoft Excel, specifically when using older PDF versions like 1.6.
- Observed behavior
- The digital signature renders as a picture rather than a standard cryptographic signature block, though printing to PDF seems to bypass the error.
Ensure your PDF reader is updated to the latest version and verify whether the issue happens across all documents or just specific files exported from your spreadsheet software.
Use Microsoft Print to PDF
Bypass the older PDF 1.6 formatting constraints by generating a fresh, compliant PDF spool file using the system's virtual printer.
Exporting directly to PDF using older standards (like PDF 1.6 or earlier) can cause compatibility issues with modern cryptographic signature layers. Using the built-in Windows 'Print to PDF' feature creates a flattened, standards-compliant document that supports standard digital signatures.
Launch your spreadsheet software and open the workbook you need to sign.
Navigate to File > Print. In the Printer dropdown menu, select 'Microsoft Print to PDF' instead of your physical printer or default PDF exporter.
Click Print, choose a destination folder to save your new PDF file, and then open it in Adobe Acrobat to apply your digital signature.
Create a New Digital ID
Generate a fresh digital certificate to rule out issues caused by corrupted or outdated digital ID profiles.
Export and Sign PDFs Directly in WPS Office
Avoid compatibility issues with older PDF versions by using WPS Office. It provides native, high-quality PDF exporting and built-in digital signature tools to ensure your documents remain secure and professional.
- 1. Open your spreadsheet: Launch WPS Office and open your workbook or document.
- 2. Export as PDF: Go to the Menu and click 'Export to PDF' to generate a modern, standards-compliant PDF document.
- 3. Open in WPS PDF: Open the newly created PDF file using the built-in WPS PDF tool.
- 4. Apply signature: Navigate to the Protect tab, click on 'Sign', and insert your secure digital signature without worrying about image degradation.
Frequently Asked Questions
Why does my digital signature look like a pixelated picture?
This usually happens when the PDF is saved using an older standard (like PDF 1.6) that struggles to render modern cryptographic signature layers, prompting the software to flatten them into low-quality images instead.
Does my Windows version affect how digital signatures display?
Yes, outdated operating systems or missing root certificate updates can prevent PDF readers from properly validating and displaying the cryptographic elements of a signature, leading to display errors.
How can I check if my signature is actually an image or a true digital signature?
In your PDF reader, click on the signature panel. A true digital signature will show certificate details, validation status, and time stamps, whereas an image will just be selectable as a graphic element with no cryptographic data.
What is the difference between an electronic signature and a digital signature?
An electronic signature is often just a typed name or a graphical image of a handwritten signature. A digital signature is backed by a cryptographic certificate that guarantees document authenticity and prevents tampering.
