IIIF and the Universal Viewer


The IIIF-based Universal Viewer is the new version of the Wellcome Player. Its data model allows for interoperability with image resources the world over.

The International Image Interoperability Framework

Digirati started thinking about the Player in 2011, when we first started working with the Wellcome Library.

The Wellcome Library knew about silos – and they didn’t want an off-the-shelf “digital library product” to add to the growing collection of systems they already had – the library catalogue, the archives database, image library software, digitisation workflow and digital asset management systems.

So we built a Digital Delivery System to glue these existing systems together. We arrived at the package model gradually by discovering what the Wellcome Player needed.

During our work in building the library digital delivery infrastructure we repeated a process that had happened many times over in libraries and cultural heritage institutions around the world – building a full stack of server and viewing technology with an ad hoc, bespoke API in the middle.

Even though we successfully avoided a silo in library infrastructure, we created a different sort of silo – our own way of doing something that is similar to but incompatible with the library next door (which happens to be the British Library in this case). You cannot point the Wellcome Player at the British Library’s APIs, and the British Library can't render the Wellcome Library’s digitised collections by consuming its packages in their existing viewers.

While institutions have different preservation infrastructure, and have different requirements for viewing technologies, the API for image delivery and the “package” metadata for presentation can be standardised, as long as those standards are rich enough to describe everything that viewing technologies need, and can be extended for particular use cases but still be consumed by baseline viewers.

iiif logo These standards now exist as the International Image Interoperability Framework.

Some institutions might want to present medieval manuscripts in sophisticated tools for scholars. Others might want to present simpler interfaces for general public consumption of First World War letters. Different viewers are appropriate in each case. The Wellcome Player was designed to be suitable for a wide range of this scale of use. It appears on the “canonical” page-per-item for the library’s digitised material, and it appears embedded in blog posts and elsewhere. It is rich enough to present the digitised material in a variety of scenarios but simple enough to be obvious in its use and purpose.

Digirati have been working with the British Library on their Universal Viewer project. This took the Wellcome Player as a starting point and adds many new features, and is 100% IIIF. IIIF will be the British Library’s standard format for presenting digitised collections, replacing more than two dozen legacy players and viewers. A large and growing number of institutions are adopting IIIF, and there is an emerging ecosystem of viewers, middleware and image server software that implements the standard.

We strongly encourage any new work in this field to be based on IIIF. The Wellcome-Player-based Universal Viewer should be the starting point for new implementers:


But I have audio, video and other non-image content!

IIIF stands for International Image Interoperability Framework – that is, it has been designed around concepts of canvas and image and arose from the needs of manuscript collections in particular. The original Wellcome Player has a modular framework that handles audio, video, PDFs and potentially any other format that someone can write a module for (for example 3D models or musical scores). The Wellcome package format is a wrapper around any kind of potential asset.

The Wellcome Library or British Library could use IIIF for all assets that are image sequences (digitised books, archives, artworks) but retain the package format for audio, video, born-digital and other formats. This feels less than satisfactory; if the Wellcome Library switches to IIIF as the package format (the packages are replaced by IIIF manifests), there should be as much consistency as possible in the metadata for all asset types. If the subject of the manifest is a video or a mixed-media sequence (a video and its transcript) there is much in IIIF that could be directly used; the overall structure, the use of Open Annotation, the general style of the format. Only the things that need to be different should be different.

This implies an as yet non-existent framework – IxIF, where the x can be anything; a superset of IIIF. As new types of x are added we need to determine the vocabulary used. For example, a video’s keyframes and segments can be identified by Open Annotation-style metadata, and the video can be contained in a manifest that conveys non-media specific information in a consistent way.

The need for IxIF has been made clear by many of the institutions participating in IIIF, and work has already begun on extending the This is something the Wellcome Library and the British Library can address next year. For now, the package format is still the primary format for the Wellcome Player. In the future it is more likely implementers will want an IIIF-based approach, for interoperability. The Wellcome Player will continue to support both formats, and will be a proving ground for extending the IIIF approach to items that are not presented as image sequences.

Where next?