What Is File Metadata?
Metadata is data about your files — not the content itself, but the attributes that describe it: when a photo was taken, what camera captured it, where in the world it was shot, who authored a document, how long an audio file is.
On macOS, most metadata is stored in two places:
- Embedded in the file: EXIF data in photos, ID3 tags in audio, XMP/IPTC in documents. This metadata travels with the file when you move or copy it.
- In the Spotlight index: macOS reads embedded metadata through
mdimporterplugins and stores it in the index askMDItemattributes. This makes it queryable without opening each file.
Understanding how the Spotlight index works helps clarify why metadata search is fast: you're querying a pre-built database, not reading thousands of files.
What macOS Knows About Your Files
Photos and Images
- Date taken (
kMDItemContentCreationDate) - Camera make and model (
kMDItemAcquisitionMake,kMDItemAcquisitionModel) - GPS latitude and longitude (
kMDItemGPSLatitude,kMDItemGPSLongitude) - GPS altitude (
kMDItemGPSAltitude) - Shutter speed (
kMDItemExposureTimeSeconds) - Aperture (
kMDItemFNumber) - ISO (
kMDItemISOSpeed) - Pixel dimensions (
kMDItemPixelWidth,kMDItemPixelHeight) - Color space (
kMDItemColorSpace) - Flash used (
kMDItemFlashOnOff) - Orientation (
kMDItemOrientation)
Documents
- Author (
kMDItemAuthors) - Title (
kMDItemTitle) - Subject (
kMDItemSubject) - Keywords (
kMDItemKeywords) - Word count (
kMDItemNumberOfPages,kMDItemWordCount) - Application that created the file (
kMDItemCreator) - Text content (full-text search via
kMDItemTextContent)
Audio and Video
- Duration (
kMDItemDurationSeconds) - Sample rate (
kMDItemAudioSampleRate) - Bit depth (
kMDItemAudioBitDepth) - Codec (
kMDItemCodecs) - Bit rate (
kMDItemAudioBitRate) - Number of channels (
kMDItemAudioChannelCount) - Video dimensions (
kMDItemPixelWidth,kMDItemPixelHeight) - Frame rate (
kMDItemVideoFrameRate)
All Files
- File name, extension, size, path
- Date created, date modified, date last opened
- Kind (
kMDItemKind): "JPEG image," "PDF document," etc. - Finder tags and color labels
- File comment (
kMDItemFinderComment)
Practical Examples with HoudahSpot
Here are four real search scenarios that would be impossible in Finder but straightforward in HoudahSpot.
Example 1: RAW photos from a specific trip
You want all RAW files taken in Iceland during a three-week trip in October 2024.
- Kind: is Image
- File extension: is ARW (or CR3, RAF, NEF — your camera's RAW format)
- Date taken: is after October 1, 2024 AND is before October 22, 2024
- GPS Latitude: is between 63 and 66 (approximate Iceland latitude range)
Result: only the files you're looking for, regardless of where they're stored on your Mac.
Example 2: Large video files for archiving
You want to find video files larger than 2GB that you haven't opened in over a year — candidates for moving to external storage.
- Kind: is Movie
- File size: is greater than 2 GB
- Last opened: is before [one year ago]
Example 3: Documents you wrote last quarter
You need all Word and Pages documents where you're listed as the author, modified in Q4 2024.
- Kind: is Document
- Document author: contains [your name]
- Date modified: is after October 1, 2024 AND is before January 1, 2025
Example 4: High-resolution audio files
You're organizing your audio library and want to identify all files with a sample rate above 44.1kHz (hi-res audio).
- Kind: is Music (or Audio)
- Audio sample rate: is greater than 44100
How to Build a Metadata Search in HoudahSpot
- Open HoudahSpot. The query builder is in the "Refine" section at the top of the "Search" pane; results appear on the right.
- Click the + button to add a criterion row.
- In the first dropdown, select the metadata attribute — for example, Latitude, Device Make, or Document Author. Use the search field in the dropdown to find any attribute quickly.
- Set the comparison operator (contains, equals, is greater than…) and enter your value.
- Add more rows to narrow results further. By default, additional rows use AND logic — all must match. You can add nested groups to combine AND, OR, and NOT logic.
- Search starts when your are ready for a first pass.
- Once the search is running, results update live as you add or change criteria.
HoudahSpot's attribute picker includes hundreds of kMDItem attributes organized by category (image, audio, document, etc.). If you're not sure which attribute name to use, type a keyword in the search field — "GPS," "author," "codec" — and the relevant attributes will appear.
For an even more powerful workflow, pair metadata search with iterative refinement — start broad and add conditions as you learn from the results.