What Is Metadata?
Metadata is data about data — information embedded in files that describes the file's properties, history, and context. Unlike the content you intentionally create (the text of a document, the subject of a photo), metadata is often created automatically and invisibly.
When you take a photo, your phone may embed your GPS coordinates. When you write a document, your word processor records your name, editing time, and revision history. When you send a file, these invisible details travel with it.
Types of Metadata in Common File Formats
Photo Metadata (EXIF):
Digital photos contain extensive metadata in the EXIF (Exchangeable Image File Format) standard:
- GPS coordinates of where the photo was taken
- Date and time (to the second)
- Camera model and serial number
- Lens and aperture settings
- Device orientation
- Sometimes: thumbnail of the original image even after cropping
This means a photo you share online can reveal exactly where and when it was taken, and what device took it.
Document Metadata (DOCX, PDF):
Microsoft Word, Google Docs, and PDF files embed:
- Author name (from your account settings)
- Organization name
- Document creation and modification dates
- Revision history and version data
- Comments and tracked changes (may be hidden but embedded)
- Software used to create the document
Spreadsheet Metadata
Similar to document metadata plus formulas and hidden cell data that may contain sensitive information.
Audio and Video Metadata
Creation software, creation date, GPS (for mobile recordings), device information.
Why Metadata Privacy Matters
Investigative exposure: Journalists who shared documents revealing their location through photo EXIF data have been identified.
Whistleblower identification: Document metadata containing author names and organization information has been used to identify document sources.
Location tracking: Sharing photos from your home, workplace, or sensitive locations can reveal those locations through EXIF data.
Professional privacy: Document metadata may reveal internal organizational information (previous author names, revision history showing sensitive edits).
How to Remove Metadata
Windows — File Properties
Right-click any file > Properties > Details tab > Remove Properties and Personal Information > Create a copy with all possible properties removed.
macOS — Preview (for images)
Preview > Tools > Show Inspector > Exif — metadata is visible. For removal, use ImageOptim or export via File > Export (strips some metadata).
For Photos on iPhone
Sharing photos through the iPhone Messages app strips location metadata by default. Sharing via email may not. iOS asks permission to share location in photos.
ExifTool (Cross-platform, Command Line)
The most comprehensive tool for metadata management. Remove all metadata: exiftool -all= filename.jpg
For bulk processing: exiftool -all= -r /folder/path/
PDF Metadata Removal
Adobe Acrobat Pro: File > Properties > Description (manually clear fields). For free removal, ExifTool also handles PDFs.
Document Privacy Before Sharing (Word/LibreOffice)
Before sharing any document, use: Word: File > Info > Check for Issues > Inspect Document > Remove all found metadata LibreOffice: File > Properties — clear personal information
Email Clients and Metadata
Most email clients strip or do not transmit file system metadata when attachments are sent. However, embedded document metadata travels with attachments.
Metadata and Email Privacy
When using Temp90 for registrations, the registration itself protects email identity. File metadata is a separate privacy consideration for files shared through any channel — including email sent from Temp90-registered accounts.
If you are sharing sensitive documents, remove metadata before uploading or emailing regardless of which email service you use.
Frequently Asked Questions
Does posting a photo to social media strip its metadata?
Major platforms (Instagram, Facebook, Twitter) typically strip EXIF metadata from uploaded photos. However, the platforms themselves retain this metadata for their internal use and may share it with advertising partners.
How do I check what metadata is in a file?
Windows: Right-click > Properties > Details. macOS: Get Info (Cmd+I). For comprehensive viewing, install ExifTool and run: exiftool filename.
Can I selectively remove only GPS metadata from photos while keeping other EXIF data?
Yes. ExifTool: exiftool -gps:all= filename.jpg removes only GPS tags while preserving other metadata.
Conclusion
Metadata is the invisible layer of information attached to every digital file. Understanding what it contains and removing it before sharing sensitive files is an important privacy practice — particularly for photos that embed GPS coordinates and documents that embed author and revision information. File metadata removal and email identity protection through Temp90 address different privacy dimensions and are most effective when used together.