Every photo carries a second layer you never see in the frame. Open the file properties and you’ll find the camera model, the lens, the shutter speed, the exact second the shutter fired, and sometimes the GPS coordinates of the spot where you stood. Add captions or keywords in an editor, and those travel with the file too.
That hidden layer is what makes sorting, searching, and renaming photos possible. It’s also easy to damage, easy to misread, and easy to leak. This guide covers the three metadata standards you’ll actually run into, what each one holds, and the mistakes that cost people the most time.
Three Standards, Three Jobs
EXIF, IPTC, and XMP are often lumped together as “the metadata,” but they were created by different groups for different reasons. Knowing which is which explains a lot of strange behavior later on.
EXIF: What the Camera Recorded
EXIF (Exchangeable Image File Format) is written by the camera or phone at the moment of capture. It’s technical and largely automatic:
- capture date and time, plus separate fields for when the image was digitized and last modified;
- camera make and model, lens, and on many bodies a serial number;
- exposure settings: shutter speed, aperture, ISO, focal length, flash, metering mode;
- the Orientation tag, which tells software how to rotate the image for display;
- GPS coordinates, altitude, and direction, if location was enabled;
- an embedded thumbnail for quick previews.
EXIF lives inside JPEG, TIFF, HEIC, and most RAW formats.
IPTC: What a Person Said About the Photo
IPTC metadata comes from the news industry. The International Press Telecommunications Council defined it so that photos moving between agencies and newsrooms would arrive with a caption, a byline, a copyright notice, keywords, and a location written by a human. The original format, known as IIM, dates back decades and has strict field lengths. Modern IPTC fields are mostly stored as XMP, but the names stuck: when a program says “IPTC Core,” it means descriptive fields like Creator, Headline, Description, and Keywords.
XMP: The Flexible Container
XMP (Extensible Metadata Platform) was introduced by Adobe and later standardized by ISO. It’s an XML-based format that can hold almost anything: IPTC fields, ratings and color labels, and in many editors the full list of non-destructive edits. Because it’s extensible, applications add their own namespaces, which is both its strength and its weakness. One program’s private fields may be invisible to another.
Capture Dates Are Less Reliable Than They Look
The capture date is the single most useful field in a photo archive. It’s also the one that goes wrong most often, and in quiet ways.
Time Zones
For most of its history, EXIF stored the date and time with no time zone at all. “2024-07-15 14:32:05” means 2:32 p.m. according to whatever the camera clock was set to. Fly from New York to Rome without touching the settings, and every shot from the trip is six hours off. Newer versions of the standard added offset fields, and phones usually fill them in, but many cameras don’t, and plenty of software ignores them.
The practical consequence: when you merge photos from a phone (which updates its clock automatically) and a camera (which doesn’t), the timeline interleaves wrong.
Drifting and Unset Clocks
Camera clocks drift by minutes over a year, and they reset after a dead battery to some default date in the past. If you’ve ever found a folder of photos dated January 1 of a year you didn’t own the camera, that’s why.
Which Date Is Which
Software shows several dates, and they mean different things. The EXIF original date is when the shutter fired. The file’s created and modified dates belong to the file system and change when you copy, download, or edit the file. A photo copied from a backup drive may show a “created” date of yesterday. For sorting, always use the EXIF original date when it exists, and treat file system dates as a last resort.
Practical tip: when you shoot with more than one device, photograph the same clock, such as a phone’s lock screen, with each camera at the start of the day. The difference between the recorded times and the time on the screen gives you an exact offset to correct each camera’s files later.
Sidecar Files: Metadata Next to the Photo
Some formats are awkward to write into. Proprietary RAW files are the classic case: their internal structure is undocumented, and rewriting them risks corrupting the one copy of the original you have. So editors write descriptive metadata and edit settings into a separate small file with the same base name and an .xmp extension, called a sidecar.
Sidecars are convenient, but they create a dependency. The photo and its sidecar are now a pair, and anything that separates them loses your work:
- renaming the RAW file without renaming the sidecar;
- copying only image files to a new drive with a filter that skips .xmp;
- deleting “junk” small files during a cleanup.
Naming conventions also differ. Some applications name the sidecar IMG_0412.xmp, others IMG_0412.CR3.xmp. If you move between editors, check which convention each one expects, or the second program will simply not see the first one’s keywords.
JPEG, TIFF, and DNG can hold XMP internally, so most editors write directly into those files instead of creating sidecars. That’s one reason DNG is popular as an archival format: the metadata can’t get separated from the image.
Privacy: What You Might Be Sharing
Metadata turns a harmless picture into a small dossier. A photo of your kid’s birthday cake, taken at home with location enabled, contains coordinates precise enough to find your front door. A serial number links photos from the same camera across different accounts.
Many large social platforms strip most metadata on upload, but that’s their policy, not a guarantee, and it doesn’t cover the more common paths: email attachments, cloud share links, file-transfer services, and photos posted on your own website. Those usually arrive with every field intact.
Before publishing or sending photos to people you don’t know, strip what you don’t need:
- Remove GPS fields entirely. This is the one that matters most.
- Remove camera serial numbers and owner name fields.
- Keep the copyright notice and creator fields if you want credit to travel with the file.
- Decide whether the capture date is sensitive for this particular set.
Do this on exported copies, never on your originals. Your archive should keep everything; the public version should keep only what you chose. In a batch tool like PhotoBatch this fits naturally as the last step of an export script, so you can’t forget it on the one set that mattered.
What Survives Conversion and What Doesn’t
Metadata is fragile in transit. Every time a file is resized, converted, or re-saved, the program doing it decides what to carry over, and the defaults vary widely.
- JPEG to JPEG: most editors preserve EXIF, IPTC, and XMP, but quick-and-dirty resizers and image libraries often drop all of it unless told otherwise.
- To PNG: the format added an EXIF chunk relatively late, and support remains inconsistent. Assume metadata may be lost.
- To WebP or AVIF: both formats can store EXIF and XMP, but many web-oriented encoders discard it by default to save bytes.
- Browser-based editing: images processed through an HTML canvas lose all metadata, period.
- Screenshots and messaging apps: a screenshot of a photo is a new image with no original metadata at all.
The Orientation Trap
The most visible conversion bug involves the Orientation tag. Many cameras store a portrait photo as landscape pixels plus a tag that says “rotate 90 degrees.” If a program physically rotates the pixels but leaves the tag in place, a viewer that respects the tag rotates it again, and the photo appears sideways. If a program drops the tag without rotating, the photo also appears sideways. The safe rule: when pixels are rotated, the tag should be reset to normal in the same step.
Color Profiles Count Too
The embedded ICC color profile isn’t usually called metadata, but it gets stripped by the same careless tools. A photo shot in Adobe RGB that loses its profile will look dull and flat in every browser. For web output, convert to sRGB first, then stripping the profile does no harm.
The Bottom Line
EXIF records what the camera knew, IPTC records what a person wrote, and XMP is the container that increasingly holds both. Capture dates are only as good as the clock that wrote them, sidecars only work when they stay next to their photos, and every conversion is a chance to lose data or leak it. Treat metadata as part of the photo, check it at each step, and it will keep doing the quiet work of making a large archive searchable.
