Tag Archives: exif

Metadata handled by Synology Photostation

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Last update : September 17, 2013

The following metadata for images are handled by the Photostation application of the Synology Diskstation :

—- EXIF —-

  • Make (IFD0)
  • Camera Model Name (IFD0)
  • Exposure Time (ExifIFD)
  • F Number (ExifIFD)
  • ISO (ExifIFD)
  • Exif Version (ExifIFD)
  • Date/Time Original (ExifIFD) : yyyy:mm:dd hh:mm:ss
  • GPS Version ID (GPS)
  • GPS Latitude Ref (GPS)
  • GPS Latitude (GPS)
  • GPS Longitude Ref (GPS)
  • GPS Longitude (GPS)

—- XMP —-

  • XMP Toolkit (XMP-x)
  • Region Person Display Name (XMP-MP)
  • Region Rectangle (XMP-MP) : x1, y1, x2, y2
  • Description (XMP-dc)
  • Subject (XMP-dc) : keywords

XMP-exif metadata tags are not recognised.

DNG : Digital Negative, camera raw data format

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Last update : January 7, 2016

DNG

Digital Negative

Digital Negative (DNG) is an public archival open raw image format owned by Adobe used for digital photography. It was launched in 2004. DNG is based on the TIFF/EP standard format, and mandates significant use of metadata. Exploitation of the file format is royalty free.

Adobe provides the Digital Negative Specification, a free Adobe DNG Converter (version 6.3), which easily translates raw files from many of today’s popular cameras, an SDK (Software Development Kit) and an DNG Profile Editor.

DNG is supported by various camera providers  and photographic software developers (Adobe Photoshop, Adobe Lightroom, …). DNG is also supported by ExifTool, a platform-independent Perl library plus a command-line application for reading, writing and editing meta information in a wide variety of files, developed by Phil Harvey. ExifTool is also available as a stand-alone Windows executable and a Macintosh OS X package. The current version is 10.09 published on January 4, 2016.

Exif, IPTC, XMP

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Last update : August 25, 2013

Exif (Exchangeable image file format) is a specification for the image file format used by digital cameras and scanners. The specification uses the existing JPEG, TIFF Rev. 6.0, and RIFF WAV file formats, with the addition of specific metadata tags. It is not supported in JPEG 2000, PNG, or GIF.

Exif was created by the Japan Electronic Industries Development Association (JEIDA).

The metadata tags defined in the Exif standard cover a broad spectrum :

  • Date and time information
  • Camera settings (camera model and make, orientation, aperture, shutter speed, focal length, metering mode, ISO speed, …)
  • Thumbnails for previewing the picture
  • Geolocation
  • Descriptions
  • Copyright

The most used tool to edit Exif informations is the ExifTool by Phil Harvey. Another very useful tool is PhotoME (Photo Metadata Editor) developped by Jens Duttke which handles also embedded color (.icc) profiles.

There exist other standards to add metadata to files : IPTC (Information Interchange Model),  XMP (Extensible Metadata Platform), … Both standards allow to embed informations about authors, locations, countries, subjects etc in the image files.

IPTC was developed in the early 1990s by the International Press Telecommunications Council (IPTC) to expedite the international exchange of news among newspapers and news agencies (IPTC Photo Metadata Standards : IPTC Core and IPTC Extension). The older IPTC metadata specification (IPTC-IIM) was frozen in 1997, and the IPTC organisation has been recommending the use of the XMP-based IPTC Core specifcation since 2004.

The ExifTool (current version 9.35 released on August 17, 2013) handles also IPTC and XMP metadata. A GUI (ExiftoolGUI : current version 5.15 released on January 8, 2013) for the ExifTool has been developed by Bogdan Hrastnik.

Another great utility allowing to read and write Exif, IPTC and XMP metadata is XnView, developed by Pierre Gougelet. This program handles more than 400 graphic file formats for import and more than 50 formats for export. A new project called XnViewMP (MP stands for multi platform) supports full multicode. Version 0.61 was released on July 18, 2013.

A C++ library and a command line utility to manage image metadata, called Exiv2, is available as free software and with a commercial license, and is used in many projects.The development of Exiv2 is lead by Andreas Huggel. Version Exiv2 0.23 was released on April, 2012.

Tags and other properties of a file can de added or modified in the Windows Explorer Detail Pane or in the Properties Pane.

The following list provides some useful guides about the right use of metadata in images and in other multimedia files :