1.0 Adding the IPTC metadata
After a photograph has been taken and processed, it might be necessary to add the International Press Telecommunications Council (IPTC) metadata before it can be published. If your image editing software does not support adding of IPTC metadata to the image, you can accomplish this is by using the exiv2 command in Linux.
2.0 An example
Suppose we have an image file, example.jpg and we wish to add the metadata for the headline and caption fields. We can do that using the exiv2 command.
$ exiv2 -M "add Iptc.Application2.Headline An example headline" example.jpg $ exiv2 -M "add Iptc.Application2.Caption An example caption." example.jpg
3.0 Image metadata
Image metadata gives information about the image. Exif (Exchangeable image file format) metadata is the most common as it is created by the camera when the image is captured. Exif data comprises of the time stamp of the image capture, camera settings like the shutter speed, aperture value, ISO sensitivity, white balance, etc. IPTC (International Press Telecommunications Council) metadata standard aims at embedding captions, tags, time stamps, rights and licensing information in the image file. Similarly, XMP (Extensible Metadata Platform) is a standard for serialization and exchange of standard and custom image metadata. In the rest of this tutorial we will focus on the IPTC metadata.
4.0 exiv2 command
exiv2 is a command for read and write of Exif, IPTC and XMP metadata fields in image files. exiv2 supports jpeg, png, gif, bmp, tiff and more image files. It also supports raw camera files like CR2, NEF, etc.
The exiv2 command syntax is,
exiv2 [options] [action] file ...
Both options and action are optional. The command exiv2 file prints the Exif data for the file. For example,
$ exiv2 example.jpg File name : example.jpg File size : 30735668 Bytes MIME type : image/jpeg Image size : 6024 x 4024 Camera make : XXXXX CORPORATION Camera model : XXXXX XXXX Image timestamp : 2017:10:03 11:56:03 Image number : Exposure time : 1/800 s Aperture : F18 Exposure bias : 0 EV Flash : Flash bias : Focal length : 24.0 mm (35 mm equivalent: 24.0 mm) Subject distance: ISO speed : 900 Exposure mode : Manual Metering mode : Multi-segment Macro mode : Image quality : RAW Exif Resolution : White balance : AUTO1 Thumbnail : None Copyright : John Doe Exif comment :
We can print the IPTC metadata using the exiv2 -pi filename command.
$ exiv2 -pi example.jpg Iptc.Application2.Headline String 19 An example headline Iptc.Application2.ObjectAttribute String 24 Object attribute - Genre Iptc.Application2.ObjectName String 9 The title Iptc.Application2.Subject String 9 Subject-1 Iptc.Application2.Subject String 9 Subject-2 Iptc.Application2.Subject String 9 Subject-3 Iptc.Application2.Keywords String 10 Keywords-1 Iptc.Application2.Keywords String 10 Keywords-2 Iptc.Application2.Keywords String 10 Keywords-3 Iptc.Application2.SpecialInstructions String 20 Special Instructions Iptc.Application2.DateCreated Date 8 2017-10-03 Iptc.Application2.TimeCreated Time 11 11:56:03+05:30 Iptc.Application2.Byline String 9 Creator-1 Iptc.Application2.BylineTitle String 19 Creator's Job Title Iptc.Application2.City String 4 City Iptc.Application2.SubLocation String 11 Sublocation Iptc.Application2.ProvinceState String 17 Province or State Iptc.Application2.CountryCode String 3 AAA Iptc.Application2.CountryName String 12 Country Name Iptc.Application2.TransmissionReference String 6 Job Id Iptc.Application2.Credit String 11 Credit Line Iptc.Application2.Source String 6 Source Iptc.Application2.Copyright String 16 Copyright notice Iptc.Application2.Caption String 25 The description (caption) Iptc.Application2.Writer String 18 Description writer Iptc.Application2.RecordVersion Short 1 5
