.. This is part of the Photini documentation.
   Copyright (C)  2012-15  Jim Easterbrook.
   See the file ../DOC_LICENSE.txt for copying condidions.

Tag reference
=============

This section lists the "mapping" from Photini's field names (such as "Title / Object Name") to the EXIF / XMP / IPTC tags the data is stored in.
The tag names are those used by the Exiv2 library.
See http://exiv2.org/metadata.html for more detail.

As far as possible Photini follows the `Metadata Working Group <http://www.metadataworkinggroup.org/>`_ (MWG) `Guidelines for Handling Image Metadata <http://www.metadataworkinggroup.org/specs/>`_.
These specify the mapping between tags in EXIF, XMP and IPTC, and say how software should reconcile any differences between information stored in equivalent tags.

Primary tags
------------

These tags are where Photini stores its metadata.
(IPTC tags are only used if they already exist in the file, in line with the MWG guidelines.)

Note that "Title / Object Name" and "Keywords" are not stored in EXIF.
You may prefer not to use these fields to ensure compatibility with software that only handles EXIF.

=======================  ==================================================  =========================  ==================
Photini field            EXIF tag                                            XMP tag                    IPTC tag
=======================  ==================================================  =========================  ==================
Title / Object Name                                                          Xmp.dc.title               Iptc.Application2.ObjectName
Description / Caption    Exif.Image.ImageDescription                         Xmp.dc.description         Iptc.Application2.Caption
Keywords                                                                     Xmp.dc.subject             Iptc.Application2.Keywords
Copyright                Exif.Image.Copyright                                Xmp.dc.rights              Iptc.Application2.Copyright
Creator / Artist         Exif.Image.Artist                                   Xmp.dc.creator             Iptc.Application2.Byline
Date and time Taken      Exif.Photo.DateTimeOriginal                         Xmp.photoshop.DateCreated  Iptc.Application2.DateCreated Iptc.Application2.TimeCreated
Date and time Digitised  Exif.Photo.DateTimeDigitized                        Xmp.xmp.CreateDate         Iptc.Application2.DigitizationDate  Iptc.Application2.DigitizationTime
Date and time Modified   Exif.Image.DateTime                                 Xmp.xmp.ModifyDate
Orientation              Exif.Image.Orientation
Latitude, longitude      Exif.GPSInfo.GPSLatitude Exif.GPSInfo.GPSLongitude
=======================  ==================================================  =========================  ==================

Secondary tags
--------------

Photini reads information from these tags and merges it with information from the primary tags.
These tags are deleted when the corresponding primary tags are saved.

=======================  ===========================  ==========================================  ==================
Photini field            EXIF tag                     XMP tag                                     IPTC tag
=======================  ===========================  ==========================================  ==================
Title / Object Name                                                                               Iptc.Application2.Headline
Description / Caption                                 Xmp.tiff.ImageDescription
Keywords                 
Copyright                                             Xmp.tiff.Copyright
Creator / Artist                                      Xmp.tiff.Artist
Date and time Taken      Exif.Image.DateTimeOriginal  Xmp.exif.DateTimeOriginal
Date and time Digitised                               Xmp.exif.DateTimeDigitized
Date and time Modified                                Xmp.tiff.DateTime
Orientation                                           Xmp.tiff.Orientation
Latitude, longitude                                   Xmp.exif.GPSLatitude Xmp.exif.GPSLongitude
=======================  ===========================  ==========================================  ==================

