Should metadata be permanent?

About The Author

CNET Editor

Lexy spent her formative years taking a lot of photos and dreaming in technicolour. Nothing much has changed now she's covering all things photography related for CNET.

Photographers always want to ensure that their photos, and the information about them, will last as long as possible. EXIF data is a very useful way of ensuring that the date of creation, exposure settings and even copyright information accompanies every digital photo. But should this data be permanently applied?

(I/0 - Lost Bits 5 image by Carsten Mueller, royalty free)

The International Press Telecommunications Council (IPTC) in London, the American Association of Advertising Agencies (4As) and the Association of National Advertisers (ANA) have banded together to take the issue of data persistence one step further by proposing that permanent metadata be applied to images, text, audio and video files. The Embedded Metadata Manifesto is based on five principles:

  1. Metadata is essential to describe, identify and track digital media, and should be applied to all media items that are exchanged as files or by other means such as data streams
  2. Media file formats should provide the means to embed metadata in ways that can be read and handled by different software systems
  3. Metadata fields, their semantics (including labels on the user interface) and values should not be changed across metadata formats
  4. Copyright-management information metadata must never be removed from the files
  5. Other metadata should only be removed from files by agreement with their copyright holders.

As cameras, mobile phones and other devices evolve to include more and more specific information embedded into files that they create, what are the ramifications of having identifying information included in every single digital file?

In some cases, it's incredibly important, such as identifying a photographer who created a particular piece of work, or inserting the GPS coordinates of a holiday snap so it can be plotted on a map. There are, however, plenty of grey areas that illustrate the potential problems of never being able to strip metadata from a file. Imagine a whistle-blowing case involving photographic evidence, where the metadata clearly reveals who took the photo.

The manifesto also doesn't seem to address issues of data tampering or manipulation. We've seen numerous cases where photo-encryption systems have been cracked, showing that an obviously manipulated image is an original file created by a camera in question. There is nothing to stop similar methodologies being developed that could change the metadata to imply that another person created an image. Conversely, the use cases for the Embedded Metadata Manifesto are plentiful amongst museums and other cultural institutions that need to have a persistent metadata state.

The consortium of organisations proposing these guidelines is suggesting that metadata be presented in the IPTC format, rather than the more standard EXIF, which most digital cameras automatically create each time a photo is created. At the time of writing, the majority of organisations supporting the manifesto are photo agencies and groups representing professional photographers.

Nevertheless, should such a manifesto be adopted by manufacturers and content creators, there is always the possibility that this information could be used to track those who create (authorised or unauthorised) copies of this material with persistent metadata. In some respects, this is already happening now, such as the iTunes Store, which appends its own metadata to purchases, including the name of the person who bought the file. At the moment, this can be removed, but, should the consortium get its way, this wouldn't be possible without requesting permission from the copyright owner.

At this stage, the manifesto is just that — a document. But it raises an important discussion about the sort of information being stored within metadata, and that your content-creation devices are probably capturing more data than you think.

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JamesM1 posted a comment   
Australia

Well it is important when it comes to indexing from Google, Yahoo and Bing, but that is only part of, but we need it to catalog articles in a website

 

IptcMichael posted a comment   
United Kingdom

Hi Lexy

I'm the lead of the IPTC Photo Metadata Working Group which has created the Embedded Metadata Manifesto (EMM) and would like to comment on your reply to DavidR7:
- the EMM has a focus on professional workflows as the involved parties are typlically interested in adding metadata to an image and that they are not lost in the workflow.
- the EMM does not request any action to make metadata for photos mandatory by law - applying metadata should be left to the free will of the owner of a photo.
- the EMM is about how persons, organisations or companies should deal with metadata and what support for that is required by software.
- the EMM claims that metadata should be permanent but that does not mean that each individual value must not be changed - this depends on the type of value, e.g. a copyright owner may change in a workflow and therefore the metadata must reflect this.
- sorry, but I don't share your view about which metadata schemas are used. We at the IPTC know that our metadata schema is widely used both by consumer and professional photographers. Adobe added IPTC metadata in 1995 to its Photoshop, other software makers followed quickly and since then fields like Description/Caption, Creator, Keyword, City/State/Country, and Copyright Notice are used by millions of consumers.
- Exif metadata are the metadata which are created by the camera and some software manages them as read-only values - which is ok as there is no need to change the exposure time of focal lenght. But Exif provides no means to add e.g. keywords.
- a short comment on an endless story: how to prevent metadata values from being modified. My view is that there are no easy to implement ways for doing this as there are no ways to stop software from changing bytes in an image file. The only reasonable approach would be to add a digital signature to the applied metadata. If metadata are changed after that point a warning should be raised - but that's all what can be done. This would require that each photographer has her or his own secure authentication certificate - this is not realistic for consumers.

Michael

 

DavidR7 posted a comment   

As one of the co-authors of the original "Metadata Manifesto" (back in 2006) and having been involved in the most recent initiative (see http://www.embeddedmetadata.org/ for the actual site) I have some concerns with the points in this article. I'm trying to understand how Alexandra Savvides came to these conclusions, but having some difficulties.

Did she visit the actual website mentioned in the original press release, or only read the press release and then make a number of assumptions?

I ask, as I find the over-emphasis on "Exif" metadata in this post a bit puzzling. The Embedded Metadata Manifesto initiative talks about "embedded information" in a file, and Exif is only one of a number of types of metadata; and one that primarily only present in digital still images (note that this initiative not only concerns digital still images, but also audio, video and other media files).

As noted on the site, this manifesto defines five guiding principles for creating and storing metadata, so that important data is carried with the file wherever possible. And "...is addressed to the parties adding and managing metadata and to the vendors of hardware and software whose systems enable media and metadata workflows."

As one example, when a digital file travels through various systems and workflows there are many points where the file may be changed-- and not always for the better. How would you feel if all of the embedded information in the MP3 music files you placed in an online cloud service had their embedded information automatically removed from the files on upload? What if you didn't discover this until after you had a hard drive crash, and had downloaded all of your files -- only to find that all you had were filenames? Would you feel different about these five principles (http://www.embeddedmetadata.org/embedded-metatdata-manifesto.php) after having to play and then identify every single album, artist, track name, etc and write that information back into the files so you could use them in your music player?

I ask, because this is where we are currently with many photo sharing and social media systems when it comes to digital still images. Take a look at the preliminary results of the "Preservation of Photo Metadata by Social Media Websites" survey (http://www.controlledvocabulary.com/socialmedia/) for an idea of what I'm talking about.

After reading a few of these referenced pages, do you still feel the same way about this initiative?

David

 

Lexy Savvides posted a reply   
Australia

Hi David,

Thanks for your response. Am keen to create discussion around this particular initiative and, indeed, metadata in relation to photography more generally. As you may have gathered from the introduction to the piece, I have approached this from a consumer and photographer's perspective rather than elaborate on the more complex use-case scenarios implied by the Manifesto (note the clear link to it in the body copy and the mention that the Manifesto extends to files beyond digital images). Given this perspective it shouldn't be such a big stretch to make the link between what the manifesto is outlining and framing it with a reference to EXIF data (mentioned twice in the article) given that this is what a majority of photographers associate metadata with in their workflow.

It's also very reasonable to bring this into a discussion surrounding image creation, even though as you quote the manifesto "...is addressed to the parties adding and managing metadata and to the vendors of hardware and software whose systems enable media and metadata workflows." - which most certainly includes camera manufacturers, creators of image management software and so on that are essential tools for work which is created by consumers. Why would it not be appropriate to bring these concerns to consumers who may not realise the metadata that is automatically being created by either their device or software program without their knowledge? The survey you linked to in regards to social media sites is particularly interesting in how sites are (currently) dealing with photographic metadata. However, for data that already exists on these services, should the manifesto be adopted in a more widespread manner, how would users go about re-classifying and altering the metadata that does or does not exist in images already uploaded without a lengthy re-uploading process? The manifesto raises some salient points which I referred to in the article, but again the potential for files (not just photographs) containing personally identifiable information which cannot be removed raises many privacy issues which go beyond the scope of this article and indeed this reply.

I'd also like to draw your attention to another article on the subject which raises some similar points: http://www.popphoto.com/news/2011/12/embedded-metadata-manifesto-wants-metadata-to-be-permanent as well as PetaPixel's quick take which you have already commented on: http://www.petapixel.com/2011/12/20/new-campaign-seeks-to-make-metadata-permanent/ Both articles focus again on the consumer photographer's perspective, something which perhaps the manifesto may not be directly targeted at but most definitely impacts upon.




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