What is metadata?
Metadata is literally data about other dates, and in practice this type of data can be found virtually anywhere. However, when we are talking about the digital world, it is additional information in digital files. From a user point of view, typically this metadata is invisible and unnecessary, but it is a very common part of various files, nowadays it is very often part of photographs.
Metadata in photos can supply information about the type of device that took the photo, the date, the camera settings, as well as GPS coordinates and much more. Directly in the photo we don’t see this information if we just look at the image, but in the digital file it is present.
We typically divide metadata in photos into 3 basic types, but metadata can also be found in any other type of file, whether it’s Word documents text files or anything else.
EXIF (Exchangeable Image File Format)
The basic information that the camera writes directly into the photo. This can be data types:
- camera manufacturer and model
- exposure values of the photo (shutter speed, lens aperture, ISO)
- lens used and focal length
- flash setting
- the date and time the photo was taken
- GPS coordinates (these can be recorded by phones that have a GPS module)
- many more depending on the camera manufacturer
IPTC (International Press Telecommunication Council)
This information brings additional information beyond the EXIF, and can be added both by the camera and by photo editors, for example:
- copyright information
- the author of the photograph
- description of the photograph
- keywords or tags
- XMP (Extensible Metadata Platform)
Possible extensions and other writing of metadata, typically to a file. The advantage is that metadata about multiple photos can be maintained in a single file, and then changed in a single location.
How to look at photo metadata
The easiest way is to look directly in Windows:
- Right-click on a photo and select Properties
- Go to the Details tab
- Here you can see the saved metadata
As you can see, the photo that was accidentally downloaded from the internet still has information left in it about the camera type and model as well as the settings information.
You can also view the metadata in a clearer form in graphics programs. For example, in the very popular IrfanView program, open the photo, press the i key on the keyboard, i.e. information, and then just choose whether you want to see the EXIF or IPTC data (which you can also edit straight away).
What the metadata is used for
For photographers, metadata is a very useful tool. They can sort their photos, use metadata in graphics programs, but also learn about what settings the photo was taken with and then apply the same practices to their own work. When printing photos, metadata also comes in handy because the printer can choose the optimal settings for printing from the metadata.
Robust graphics programs or experienced photographers can then also use this data to advise on why the photo failed and where there is room for improvement. Is the photo overexposed? EXIF data will immediately advise where the error was.
So the metadata definitely has its uses and it makes complete sense to store it. But it probably won’t come as a surprise that they may also contain information that you definitely don’t want to share, and that someone might need to misuse as well.
Metadata can be a security risk
Photos can contain a lot of information, such as your GPS coordinates, which can then just be entered into, for example, Google Maps, and you can immediately see where you were. combined with the date the photo was taken, also when exactly you were there. Sometimes this may not matter, but other times this can be completely confidential information.
In general, metadata should be mainly for you and your use, and not for sharing information that no one needs to know. So if you share photos on social media, for example, it’s always a good idea to delete the metadata first.
Some of these sharing networks delete metadata automatically because it’s redundant data that’s taking up space, but it’s not a good idea to rely on this. Conversely, different networks can use this metadata to target advertising, for example, or generally bundle what you do, when, where and with whom. Thus, nothing for social networks to poke their noses into.
How to delete metadata from photos
The easiest way is to use the aforementioned IrfanView program:
- Open the photo for which you want to delete metadata
- Press Ctrl + S, or click File > Save in the menu
- A window will pop up where you choose where to save the file, in what format, and what to call it
- A window will also appear with the option to keep or, conversely, delete the metadata. If you want to delete the metadata, uncheck these items
- Save the file to delete the metadata