PDF documents are one of the most common formats for sharing sensitive information. This tutorial shows you how to embed a tracking pixel in any PDF file.
Step 1: Create a Tracking Pixel
1 Create Your Pixel
- Log in to Signal Canary
- Go to Create Canary → Document Pixel
- Enter the document name (e.g., "Q4 Financial Report")
- Optionally add the intended recipient's information
- Click Create
- Copy the Pixel URL
Step 2: Open Your PDF Editor
2 Choose Your Editor
You'll need a PDF editor that allows inserting images. Common options include:
- Adobe Acrobat Pro - Full-featured, industry standard
- Foxit PDF Editor - Affordable alternative
- PDF-XChange Editor - Free with basic features
- Any editor that supports inserting images from URLs
Step 3: Insert the Pixel
3 Embed the Tracking Pixel
- Open your PDF document in the editor
- Select Insert → Image
- Paste the Pixel URL or upload the tracking image
- Place the image in a discreet location:
- Document footer
- Header area
- White margin space
Resize the image to 1x1 pixel or place it behind text so it remains invisible to the reader while still loading when the document is opened.
Step 4: Save & Send
4 Finalize Your Document
- Save the PDF document
- Send it to your recipient via email or file sharing
- Monitor access events in your Signal Canary dashboard
Once the PDF is opened by the recipient, the access event will appear in your Signal Canary dashboard within seconds.
Supported PDF Editors
| Editor | Platform | URL Insert | Notes |
|---|---|---|---|
| Adobe Acrobat Pro | Windows, Mac | Yes | Best compatibility |
| Foxit PDF Editor | Windows, Mac | Yes | Good alternative |
| PDF-XChange | Windows | Yes | Free version available |
| LibreOffice Draw | All platforms | Limited | Free, open source |
Some PDF readers (especially web-based viewers) may not load external images by default. Desktop PDF readers like Adobe Reader provide the most reliable tracking.