Image metadata processing June 29, 2013 / Updated: October 18, 2023

Whenever a new image is discovered Zenphoto attempts to populate certain object properties from the metadata associated with the image. Images may contain both EXIF, IPTC or XMP metadata or may be accompanied by a XMP sidecar file (see xmpMetadata extension).
Zenphoto uses the formal specifications for these metadata to determine which object properties are set:

• https://exiftool.org/TagNames/EXIF.html 
• https://www.iptc.org/standards/photo-metadata/iptc-standard/
• https://www.adobe.com/devnet/xmp.html

NOTE: populating Zenphoto object properties is in addition to storing the EXIF and IPTC fields in the object. It is a service to try to populate commonly used properties from the image data.

Important note on refreshing metadata: the "Refresh metadata" utility which is accessible from the backend "Overview" page, every album-edit page and every image-edit page, will overwrite all manually added metadata with metadata embedded in the image/album.
This cannot be undone!Often multiple metadata fields will map onto a single property. In this case Zenphoto applies a precedence order to the metadata, using the highest precedence field discovered. This may cause unfortunate effects when cameras or image processing software has used these fields for their own purpose. It is always possible to disable Zenphoto from using such fields.

One other source of confusion is the unfortunate naming of the EXIF "title" field. According to the EXIF specification this is the "image description". Zenphoto honors the definition of the field.

NOTE: Should you get unexpected metadata results, especially with non-ASCII characters (Cyrillic for example), try again with the xmpMetadata extension enabled.

The following is the precedence processing order for mapping metadata to Zenphoto properties:

Zenphoto date

1. IPTC Date Created+IPTC Time Created
2. EXIF Date Time
3. EXIF Date Time Original
4. EXIF Date Time Digitized
5. the image filemtime

Zenphoto title

1. IPTC Object Name
2. IPTC Image Headline
3. the image filename with the suffix stripped off

Zenphoto description

1. IPTC Image Caption

Zenphoto location

1. IPTC SubLocation

Zenphoto city

1. IPTC City

Zenphoto state

1. IPTC State

Zenphoto country

1. IPTC Location Name

Zenphoto credit

1. IPTC ByLine
2. IPTC ImageCredit
3. IPTC Source

Zenphoto copyright

1. IPTC Copyright