Wiping Traces: Best Open Source Tools For Deleting Metadata

Photo by Anne Nygård / Unsplash

So why?

Files often contain personal information. It can be timestamps, GPS location, owner, organization, specific hardware info and more. Removing it will increase user privacy. You maybe don't need it now, but will need it later: the future isn't always predictable.

Is metadata bad?

Metadata isn't evil 'cause helpful for making collections and working with big archives, especially for searching: file managers often creating index DB heavily relied on metadata. But in enemy hands, metadata transforms into a weapon. Photo, video, PDF and office documents living their hidden internal lives covered by metadata and can tell a lot about their creator. Check all info before publishing on internet, 'cause there's no "revert" button - you can't remove anything from world web.

digiKam

digiKam, source: official website

DigiKam is a popular image organizer, licensed under GPL. The option "Clear Your Traces" seems like not well known, so let's do some promotion here ;-)
The application is definitely one of the best in photo area and supports EXIF, IPTC, or XMP metadata formats and allows you to edit also licensing, location and contact info, templates are helpful for big archives. All options live in Images -> Metadata menu; you can easily clone and remove metadata in one click for one or many photos.

Metadata Cleaner

Metadata Cleaner,  source: official website

Metadata Cleaner, an Open Source application licensed under GPL, does exactly what the name says: "Metadata Cleaner allows you to view metadata in your files and to get rid of it, as much as possible." Works with pictures, videos, EPUB and PDF formats. Not so popular like digiKam, but can be easily installed from Flathub. After first start we'll see GTK application with simple GUI: "Add Files" button, added files with numbers of identified tags and "Clean" button. Backup option also available, in cases "something go wrong". Pick "Superficial cleanup" when removing all metadata isn't an option, so user can keep most relevant one.

ExifTool

Probably, the most popular console application for editing image metadata, licensed under MIT. Big feature set, variety of supported format make this app very useful for automating metadata edition.

Supported formats:

  • Reading: EXIF, GPS, IPTC, XMP, JFIF, MakerNotes, GeoTIFF, ICC Profile, Photoshop IRB, FlashPix, AFCP, ID3, Lyrics3

  • Writing: EXIF, GPS, IPTC, XMP, JFIF, MakerNotes, GeoTIFF, ICC Profile, Photoshop IRB, AFCP

  • $ exiftool a.jpg - extract all metadata from file

  • $ exiftool -artist='Rockstar' a.jpg - add "Artist" tag

  • $ exiftool -artist=Me a.jpg b.jpg b.jpg- write multiple files

  • $ exiftool -artist="" -copyright="" c.jpg - write multiple metadata

  • $ exiftool -all='' d.jpg - remove all metadata

As you can see, the metadata writing pattern is easy: -TAG:data file, -all= option cleaning all if you messed up or just want to clean all information.

jExifToolGUI

jExifToolGUI, source: official website

The GUI for ExifTool^, written in Java and licensed under GPL. Console applications with too many options aren't always convenient, so GUI can be helpful. ExifTool installation is required too.
UX based on two big lists together with mass selection is a big win for visibility. Left list - file previews, right list - file metadata preview. Overall, functionality is about the same as in console app, if a lot of files (10 and more) and need a preview in case of image or video files, then jExifToolGUI is what you need. If you need to edit metadata in 2-3 files or just remove all metadata, better pick ExifTool.

ExifCleaner

ExifCleaner, source: official website

ExifCleaner is another GUI application based on ExifTool, licensed under MIT. Main difference between above apps is simple: metadata editing isn't supported, only cleaning. UI is super-duper easy, maybe suitable for 5yo kid. Just drag files to app window, get metadata counters and... not hard to guess - wipe it completely. Multicore processing provides a performance bust.

Supported files:

  • images: PNG, JPG, GIF, and TIFF
  • videos: M4A, MOV, QT, and MP4
  • documents: PDF

jhead

After powerful application reviews, it's time to talk about a smaller category. Jhead is a simple console program, licensed under Public Domain and designed to handle the most popular image format - JPEG. However, a lot of parameters available.

  • $ jhead i.png - show metadata info
  • $ jhead -du i.png - remove any unknown to jhead metadata
  • $ jhead -de i.png - remove EXIF metadata
  • $ jhead -di i.png - delete IPTC section
  • $ jhead -dx i.png - delete XMP section
  • $ jhead -dx i.png- delete all sections

mat2

A terminal metadata removal tool, written in Python and licensed under LGPL. Supports images, videos, documents, audio and even torrent files. Probably the one and only app from our list which supports HEIC files, used mostly on Apple devices.
A lot of console parameters are available, also the plugin for GNOME Nautilus can make your life easier, especially when visualization is needed. Ffmpeg required for video support, also bubblewrap for sandboxing, can be disabled with --no-sandbox option.

Supported formats:

  • video: avi, mp4
  • audio: off, opus, oga, spx, flac
  • images: bmp, gif, jpeg, png, tiff, svg
  • documents: pptx, xlsx, docx

How to use

  • $ mat2 i.jpg i.png - process files
  • $ mat2 --inplace i.jpg - cleanup without backup
  • $ mat2 -s i.jpg - list harmful metadata

Final note

Metadata matter, sometimes it's helpful, sometimes is it not, but cleaning is definitely easy with the right tools. And, definitely, good Open Source applications are around. Here two tools we can recommend for our readers:

  • mat2 - console application, plenty of options and solid number of supported formats
  • ExifCleaner - all above except graphical interface.

If you need any special feature, also check other applications: jhead good if you're working with images in terminal and jExifToolGUI provide good graphic interface and solid experience for batch mode experience.

Paul Nixer

Paul Nixer