dharma blues

Context

Digital Asset Management (DAM) is becoming a hot topics these days. When you’re having thousands of photos on your system and that you want tagging your souvenirs, you wish to do that once as it is quite a tedious job.

But you do not necessarily want a large bunch of tags for the same reason that having a lot of sister folders on your system does not help. More probably, you will want to nest these folders in an orderly manner.

For instance, instead of having your photos tagged as « Maricler, California, San Francisco, trees, streets and sidewalks », you may want instead having:

people
   Maricler
USA
   California
      San Francisco
      Los Angeles
      Santa Barbara
nature
   trees
city
   streets and sidewalks

Tools

In the realm of digital photos, some popular applications that enable photo tagging are:

Picasa 2.7
Picasa 3 (beta)
Microsoft Windows Live Photo Gallery
Microsoft Pro Photo Tools
Microsoft Expression Media 2
Adobe Photoshop Elements (versions 5, 6 and probably 7)
Adobe Photoshop Lightroom 2

But now, you have to read that carefully:

Your tagging system will not survive the tools that use proprietary catalogs to store your tags

As I said, you want tagging your thousands of photos only once. Fortunately, standards exist that permit you to embed these tags directly into your jpeg images. You may not have noticed but a lot of information is already inserted into your photo files. For example, your digital camera will include that kind of information in your jpeg files (extract only):

<exif:ExifVersion>0220</exif:ExifVersion>
<exif:ExposureTime>1/320</exif:ExposureTime>
<exif:ShutterSpeedValue>8321928/1000000</exif:ShutterSpeedValue>
<exif:FNumber>56/10</exif:FNumber>
<exif:ApertureValue>4970854/1000000</exif:ApertureValue>
<exif:DateTimeOriginal>2007-10-06T18:49:18-04:00</exif:DateTimeOriginal>
<exif:DateTimeDigitized>2007-10-06T18:49:18-04:00</exif:DateTimeDigitized>
...
</exif:Flash>
<exif:FlashpixVersion>0100</exif:FlashpixVersion>
<exif:ColorSpace>1</exif:ColorSpace>
<exif:ComponentsConfiguration>
<rdf:Seq>
   <rdf:li>1</rdf:li>
   <rdf:li>2</rdf:li>
   <rdf:li>3</rdf:li>
   <rdf:li>0</rdf:li>
</rdf:Seq>
</exif:ComponentsConfiguration>
<exif:CompressedBitsPerPixel>5/1</exif:CompressedBitsPerPixel>

And along with this kind of information, your tags can also be embedded in a likewise manner.

If you just want a bunch (or bag) of tags, you are probably fine. Problems start when you want hierarchical tags!

Hierarchical tags

Semi-standards appear to exist for preserving hierarchical tags. For instance, Microsoft is suffering from a kind of disorderliness as Expression Media 2 uses the symbol « | » as a tag separator to reflect hierarchy whereas the popular Windows Live Photo Gallery will use « / » (…). The default in Adobe Lightroom will retain the « | » symbol.

Just to have fun, look at this short extract from the metadata  section embedded in a sample picture (original tags in French):

<rdf:Description rdf:about=""
    xmlns:dc="http://purl.org/dc/elements/1.1/">
 <dc:title>
    <rdf:Alt>
       <rdf:li xml:lang="x-default">Maricler sur Haight Street</rdf:li>
    </rdf:Alt>
 </dc:title>
 <dc:subject>
    <rdf:Bag>
       <rdf:li>Californie</rdf:li>
       <rdf:li>Maricler</rdf:li>
       <rdf:li>San Francisco</rdf:li>
       <rdf:li>USA</rdf:li>
       <rdf:li>arbres</rdf:li>
       <rdf:li>lieux</rdf:li>
       <rdf:li>nature</rdf:li>
       <rdf:li>pays</rdf:li>
       <rdf:li>personnes</rdf:li>
       <rdf:li>rues et trottoirs</rdf:li>
       <rdf:li>règne végétal</rdf:li>
       <rdf:li>thèmes</rdf:li>
       <rdf:li>urbains</rdf:li>
    </rdf:Bag>
 </dc:subject>
 <dc:description>

<rdf:Description rdf:about=""
    xmlns:MicrosoftPhoto="http://ns.microsoft.com/photo/1.0">
 <MicrosoftPhoto:LastKeywordXMP>
    <rdf:Bag>
       <rdf:li>personnes/Maricler</rdf:li>
       <rdf:li>lieux/pays/USA/Californie/San Francisco</rdf:li>
       <rdf:li>thèmes/nature/règne végétal/arbres</rdf:li>
       <rdf:li>thèmes/lieux/urbains/rues et trottoirs</rdf:li>
    </rdf:Bag>
 </MicrosoftPhoto:LastKeywordXMP>
</rdf:Description>

<rdf:Description rdf:about=""
    xmlns:lr="http://ns.adobe.com/lightroom/1.0/">
 <lr:hierarchicalSubject>
    <rdf:Bag>
       <rdf:li>lieux|pays|USA|Californie|San Francisco</rdf:li>
       <rdf:li>personnes|Maricler</rdf:li>
       <rdf:li>thèmes|lieux|urbains|rues et trottoirs</rdf:li>
       <rdf:li>thèmes|nature|règne végétal|arbres</rdf:li>
    </rdf:Bag>
 </lr:hierarchicalSubject>
</rdf:Description>

For those of you having a codewise mentality, it’s not too hard to understand that a complete mess resides in this metadata. For instance, the last section of this extract is issued by Adobe Lightroom 2 (despite the « lightroom/1.0 » appearing in the xmlns). When you want to save the metadata of an image, Lightroom 2.0 will put the above information in your jpeg file. For sure, Microsoft Expression Media 2 will understand and show the tag hierarchy properly. But not so with Microsoft Windows Live Photo Gallery nor with the quite recent Pro Photo Tools.

In fact, Lightroom 2.0 will issue a bunch of those tags (without hierarchical information) for the rest of the universe that does not see the symbol « | » as a keyword (tag) separator.

On the other hand, Picasa 3 seems to be agnostic in this regard. It has a new feature hidden in the menu “Tools/Experimental/Show tag as album…” that will show “tag/subtag1/sub-subtag2″ as well as ”tag|subtag1/sub-subtag2″ without any complaint, but not really in a serviceable manner.

Why fussing about this matter?

In our family, we have 2 desktops and one laptop (all PCs) linked to a network attached storage (NAS) Apple Time Capsule (works well by the way!). 

Should my wife decide to tag a photo, I want to be informed of that on my system or on the laptop. But if our tagging system is dependent of a proprietary catalog, I will not be able to see that change unless there is a way to share that catalog, which is quite difficult with the actual applications. But if we know that the photo has been tagged inside the image file then everything is fine as the information for that photo (tags, caption, title, author, etc…) will travel whatever the application we use.

That’s why Digital Asset Management (DAM) is important. You work once for a said photo and that’s all.

In the meantime, big players in the field will have to talk together to synchronize their acts.

Should you have any recommendation for those of you who had to battle with this tag madness, do not hesitate to leave your comments —as I’m still pending on this matter!