Permanent Metadata

Yes that would be cool! I am getting asked that question more and more lately. Each time it reminds my of the line “this will go down on your permanent record” – a la the Violent Femmes song. John and I have discussed this topic for his blog post but I have a few more thoughts on the subject.

There are a few techniques out there that can embed or weave information into the image file itself. In all cases it will affect the image quality to some extent – you are after all changing the pixels. In one approach a piece of information like copyright info is coded into the pixels in a specific pattern so that if the image is cropped or slightly modified, pieces of the pattern can be reassembled to reveal the original copyright info. Making this more robust depends on increasing the patterning intensity which of course will degrade your image more since you are modifying it.

Another popular technique is to visually stamp the copyright info into the image directly – this is an obvious deterrent but Photoshop is a powerful tool to amend these changes by a determined thief.

XMP metadata is basically a chunk of XML jammed into various file formats – a simple idea that can be very powerful in capturing, storing and updating information directly in the assets itself – like a little database within each file. The more tools that support XMP, the more that they can exchange information and work well together at improving the workflow. What makes XMP powerful is that is can be changed and updated. But there are potential improvements that can be helpful.

Currently metadata within Adobe products can be updated by templates that append or replace information. Append will add new info if the target field is empty or can store multiple values – appending the keywords field will preserve the old keywords and add the new ones. Replace will simply replace what it there with the new info.

I’d like to see a more refined approach to this to prevent inadvertently overwriting existing fields. One idea would be to establish a lock attribute to fields and ensure that our applications are aware of this attribute – so if a field is locked and a replace action occurs, the application will warn the user. The user then needs to unlock the fields in the UI to replace the data. Making this more explicit will help reduce accidental overwrites.

Another idea that has been talked about by the IPTC is the ability to have user specific metadata. The enables a situation where each editor of metadata can apply their changes without destroying the previous user’s information. This raises a number of interesting challenges – authentication is required, you will need to log into Photoshop or at least we will need to pull the info from your computer (what if you use multiple computers with different login names?), then there are layers of access control that will be needed – do you have the permission to see my metadata? How do I manage these permissions?

Even keeping a history log of edits can become problematic if the assets is reused multiple times – for competing clients, how embarrassing would that be if they were to look in the metadata history and see the same picture has been used by their competitor?

It may be the case that metadata in the file evolves to become a “cache of convenience” with the authoritative information living on a web service. The web service model is designed to provide the authentication and permissions needed. The link between the two provided by unique IDs. In fact, unique IDs are already created by Adobe applications and stored in the XMP – that is what the XMP Media Management properties are all about. The ID model is also actively being pursued by organizations such as PLUS for referencing licensing information and Ad-ID for advertising info.

But even these XMP based IDs can be wiped out. As with anything digital, it can be hacked, broken apart and reassembled. XMP metadata is not meant to be DRM. If you want that type of protection PDF has some technology that can be useful. Even then, once the asset is free, screenshots can be taken etc.

I am interested in hearing what you think about these approaches. What else can we do to improve this situation?

Technorati Tags: , ,