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The world of metadata – descriptive data attached to digital files – is not a simple one. There is not one ubiquitous, universally-used standard way of organising metadata, there are many options to choose from. However, a few standards have been developed which have gained huge popularity with archivists, photographers, and cultural institutions. Some have even been adopted as properly-recognised international standards.
A digital file’s metadata can contain many different pieces of information,and each piece can have different content and parameters. The ways these pieces of information (or fields) are formatted and organised are called standards. But what information should be included in a standard?
Imagine you are describing an object in the physical world. Your house, for example. You are in the street, looking at the building. How would you describe it? You might start by saying that it is eight metres tall. It was built in 1986. It has 12 windows. The address is 76 High Street. The owner is George Thompson. It has a mortgage which is due to be paid off in 2020. Gas central heating. Alarm system fitted. Originally built by Harold Smith and Sons. The amount of data could be vast, and varied in format and style. You need a standard to decide what is important to include and how it should be formatted.
Note: a standard is subtly different to a schema. Schemas will be examined in a later blog post.
One of the most popular metadata standards is Dublin Core (DC), a standard which is designed to be used online for any type of digital file, with the aim of making the file more discoverable. Its simplicity is one of its strengths; Dublin Core’s fields are easy to understand and there are not too many of them; just the essentials (as the name core suggests).
DC includes the following 15 fields:
1. Title; 2. Creator; 3. Subject; 4. Description; 5. Publisher; 6. Contributor; 7. Date; 8. Type; 9. Format; 10. Identifier; 11. Source; 12. Language; 13. Relation; 14. Coverage; 15. Rights
Using these fields, the following picture could be described as follows…
1. Cheetah portrait Whipsnade Zoo
2. Warby, William
3. Big cat
4. Headshot of a cheetah at Whipsnade Zoo in England
5. Warby, William
13. IsPartOf 2010 – Whipsnade Zoo (September 19th)
14. Whipsnade Zoo
14. Bedfordshire, England, UK
For examples of how to fill-in Dublin Core fields, visit the link below: http://dublincore.org/documents/2001/04/12/usageguide/generic.shtml
A metadata standard commonly used in the world of photography is Exchangeable Image File Format (Exif). Exif metadata is automatically added to an image file by the camera as soon as the photo is taken. Almost all cameras subscribe to this standard.
Exif differs from Dublin Core because it focuses on the technical aspects of the file, rather than descriptive data designed for discoverability. However, some Exif data is useful for discoverability, such as geotagging (a feature becoming more prominent on cameras, particularly mobile phone devices).
Here’s an example (not all metadata fields are shown):
Filename – DSC_0247.JPG
Make – NIKON CORPORATION
Model – NIKON D40X
XResolution – 300
YResolution – 300
ResolutionUnit – Inch
Software – Ver.1.00
DateTime – 2012:03:26 21:49:29
ExifOffset – 216
ExposureTime – 1/250 seconds
ExposureProgram – Not defined
ISOSpeedRatings – 100
ExifVersion – 0221
DateTimeOriginal – 2012:03:18 16:11:08
DateTimeDigitized – 2012:03:18 16:11:08
CompressedBitsPerPixel – 2 (bits/pixel)
ExposureBiasValue – 0.00
MaxApertureValue – F 4.76
MeteringMode – Multi-segment
This has been a brief introduction to metadata standards, designed to give beginners a taste of how standards hold their content. Check back here soon for more articles in the series.
Images used in this article:
1. By Cjangaritas [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
2. William Warby [CC-BY-2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
3. Layla Mannings. All Rights Reserved. Used with permission.
Article written by Nick Hodder