Comparison of photo metadata and tags in other applications

This page describes how Shotwell and other photo programs import and export information through EXIF/IPTC/XMP tags. The metdata "paths" are Exiv2 tags.

Tags

Tags may contain the following information:

  • single-line photo caption ("title')
  • multi-line photo description ("notes" or "comments")
  • keywords ("tags" in some programs including Shotwell)
  • rating

EXIF

There are three tags in the standard EXIF specification that may carry relevant information.

  • Exif.Image.ImageDescription (described in the spec as "image title")

  • Exif.Photo.UserComment ("content description note")

  • Exif.Photo.MakerNote ("manufacturer notes")

Also in the standard specification are a few Windows-specific tags:

  • Exif.Image.Rating
  • Exif.Image.XPTitle
  • Exif.Image.XPComment
  • Exif.Image.XPKeywords
  • Exif.Image.XPSubject

IPTC

photo caption

  • Iptc.Application2.Caption
  • Iptc.Application2.Headline

keywords

  • Iptc.Application2.Keywords
  • Iptc.Application2.Subject
  • Iptc.Application2.Category
  • Iptc.Application2.SuppCategory

rating

  • Iptc.Application2.Urgency

XMP

photo caption

  • Xmp.dc.title
  • Xmp.photoshop.Headline

photo description

  • Xmp.dc.description

keywords

  • Xmp.dc.subject
  • Xmp.lr.hierarchicalSubject
  • Xmp.digiKam.TagsList

  • Xmp.photoshop.SupplementalCategories

rating

  • Xmp.xmp.rating

Photo Programs

Program Notes

F-Spot only really cares about keywords. It has a comment field which doesn't seem to be used for much. In addition to the regular tag metadata, it can use location XMP info to create "places" tags. See below for more details.

digiKam only uses descriptions. Multi-line or long descriptions are cut short with an ellipses in certain places, acting as captions. It can, however, modify metadata that it doesn't use in the application; this is done with specific metadata editing tools.

Picasa and WLPG (Windows Live Photo Gallery) can import keywords from multiple tags, but digiKam only grabs keywords from one set at a time.

The WLPG properties dialog lets you read and edit the "Comment" and "Subject" fields, which get written into Exif.Image.XPComment and Exif.Image.XPSubject, respectively.

On export, iPhoto strips all Xmp tags and writes relevant information into the respective IPTC tags.

Aperture offers immense fine-grain control over metadata.

F-Spot Imported Tags

F-Spot looks at the following tags during import, and imports according to below:

Title/Comment

But only uses http://ns.adobe.com/exif/1.0/UserComment

Rating

First uses Urgency, but if Rating exists uses Rating.

Location tags

Adds them as Tags to the photo. Internally F-Spot stores the IPTC tags (City, Country, Location, State) under corresponding virtual tags (only in f-spot db, not in embedded tags)

Subject / People

Adds them as Tags to the photo, no hierarchy is saved.

Ignores the following

Apps/Shotwell/PhotoTags (last edited 2013-11-23 01:25:39 by JimNelson)