Photo2Graph Metadata

JPEG Photos have 5 different types of Metadata:

Exif – Exchangable Interchange Format – this is the most basic set of metadata
IPTC -IMM (pre-XMP) – IPTC metadata is split into the legacy IPTC-IMM section and IPTC within XMP (see below)
JPEG Comments – this is a separate section of metadata allowing multiple comments to be added – these are
XMP – the Extensible Metadata Platform (XMP) includes the IPTC-IMM metadata and many new metadata.
System Data (this is system dependent e.g. but includes system file properties such as File Size, Date Created – some Windows metadata is not visible from Linux, for instance)

There can be quite a bit of overlap – for instance, the Location information (such as “City”) can be present in IPTC-IMM, and three places in XMP – Location (Legacy). LocationCreated and LocationShown – so potentially in 4 Locations.
Software should keep the XMP and non-XMP IPTC properties aligned. Most software programs will automatically put important descriptive metadata (e.g. Date Created, Description, Location) into the XMP section – so XMP should be fairly complete.
Windows (and other operating systems) will only show a subset of the metadata to users in the Properties section of Windows Explorer. For instance, most of the IPTC metadata is not visible. You would need to use other software tools to view and amend IPTC metadata. I list a few on the Software Tools page. There are a few things that happen on Windows which can be confusing:
- Keywords / Windows Tags : Windows combines together the EXIF and IPTC keywords for display of properties and searching.
- Subject : If this is not provided, Windows will show the Subject to be the same as the Title field