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Just a quick heads-up to say that we’ve had a go at incorporating InChIs and ontology terms into our PDFs with XMP. There isn’t a lot of room in an XMP packet so we’ve had to be a bit particular about what we include. InChIs: the bigger the molecule the longer the InChI, so we’ve standardized on the fixed-length InChIKey. This doesn’t mean anything on its own, so we’ve gone the Semantic Web route of including an InChI resolver HTTP URI.

In order to encourage publishers and other content producers to embed metadata into their PDFs, we have released an experimental tool called “pdfmark”, This open source tool allows you to add XMP metadata to a PDF. What’s really cool, is that if you give the tool a Crossref DOI, it will lookup the metadata in Crossref and then apply said metadata to the PDF. More detail can be found on the pdfmark page on the Crossref Labs site.

There’s a new XMP Primer (PDF) by Ron Roskiewicz (ed. Dianne Kennedy) available from XMP-Open. This is copyrighted 2008 but I only just saw this now. This is a 43 page document which provides a very gentle introduction to metadata and labelling of media and then introduces XMP into the content lifecycle and talks to the business case for using XMP. The primer covers the following areas: Introduction to Metadata Introduction to XMP XMP and the Content Lifecycle XMP in Action; Use Cases Additional XMP Resources One small gripe would be that this seems to have been prepared for US letter-sized pages and although is printable on A4 there is the slightest of clippings on the right-hand margin with no real loss of information but it does confer a sense of “incompleteness”.

Update about new XMP Library from Adobe Labs: “The new Adobe XMP Library for ActionScript is now available for download on Adobe Labs. Adobe Extensible Metadata Platform (XMP) is a labeling technology that allows you to embed data about a file, known as metadata, into the file itself. XMP is an open technology based on RDF and RDF/XML. With this new library you can read existing XMP metadata from Flash based file formats via the Adobe Flash Player.

Well, as I blogged on our web publishing blog Nascent we just went live with XMP labelling on Nature in yesterday’s double issue. We will be adding XMP to all new issues of Nature as well as rolling out across all our other titles in the next few weeks and months. The screenshots below from Acrobat (File > Properties, CMD-D / CTL-D) show what the user might see both with (bottom-left) and without (top-right) semantic markup.

For those who may be interested in the progress of XMP, Adobe’s Gunar Penikis has just announced 1 two new releases of XMP SDKs: XMP Toolkit 4.4 (with support for new file formats), and FileInfo SDK (for customizing CS4 UIs). More importantly, though, may be the new edition of the XMP spec - see here, which is bumped from a modest 112 page document to a 3-parter at 199 pages.

So, back on the old XMP tack. The simple vision from the XMP spec is that XMP packets are embedded in media files and transported along with them - and as such are relatively self-contained units, see Fig 1.

Fig. 1 - Media files with fully encapsulated descriptions.

But this is too simple. Some preliminary considerations lead us to to see why we might want to reference additional (i.e. external) sources of metadata from the original packet:

PDFs

PDFs are tightly structured and as such it can be difficult to write a new packet, or to update an existing packet. One solution proposed earlier is to embed a minimal packet which could then reference a more complete description in a standalone packet. (And in turn this standalone packet could reference additional sources of metadata.)

Images

While considerably simpler to write into web-delivery image formats (e.g. JPEG, GIF, PNG), it is the case that metadata pertinent to the image only is likely to be embedded. Also, of interest is the work from which the image is derived which is most likely to be presented externally to the image as a standalone document. (And in turn this standalone packet could reference additional sources of metadata.)

(Continues)

Now, assuming XMP is a good idea - and I think on balance it is (as blogged earlier), why are we not seeing any metadata published in scholarly media files? The only drawbacks that occur to me are:

1. Hard to write - it’s too damn difficult, no tools support, etc.

   • Hard to model - rigid, “simple” XMP data model, both complicates and constrains the RDF data model

(Continues)

Interesting post from Gunar Penikis of Adobe entitled “Permanent Metadata” Oct. ’04). 1. He talks about the the issues of embedding metadata in media and comes up with this: “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.

Been so busy looking into the technical details of XMP that I almost forgot to check out the current landcsape. Luckily I chanced on these articles by Ron Roszkiewicz for The Seybold Report (and apologies for lifting the title of this post from his last). The articles about XMP are well worth reading and chart the painful progress made to date:

• The Brief Tortured Life of XMP (July ’05)
  • [Thought Leaders Hammer out Metadata Standard] (April ’07)

    • [Metadata Persistence and “Save for Web…”] (July ’07)

    From the earlier characterization of XMP as “underachieving teenager” Roszkiewicz is cautiously optimistic that IDEAlliance’s XMP Open initiative (an initiative to advance XMP as an open industry specification) will help outreach and foster adoption of this fledgling technology.

    (Continues.)