Introduction to the DLCS

  1. Why Digirati are building the DLCS
  2. Core services
  3. Who is the DLCS for?
  4. DLCS, IIIF APIs and open standards.
  5. Hosting and DLCS-as-a-service.
  6. Find out more.


Why Digirati are building the DLCS.

Traditional digital library services for surfacing digitised content tend to be costly, bespoke applications tightly tied to the content and uses of particular institutions’ collections, or inflexible and expensive vendor-supplied monolithic applications. Integration with existing collections and their metadata is hard to do; adding new functionality expensive; and, interoperability with other content, or other applications difficult, or impossible.

The emergence of open standards around image delivery and the display of digital objects (the International Image Interoperability Framework), and the development of similar standards for content description and for annotation of digital objects (the W3C Web Annotation, and Open Annotation models) have meant that another model is possible.

The DLCS vision is to build a suite of largely self-contained services built around open standards and APIs which together cover all of the core functionality required to deliver digital content online. The DLCS services can be combined in different ways to offer flexible options for institutions looking to deliver their content online.

Core DLCS Services

Functionality includes:

  • Managed ingest pipeline for adding images, multimedia and metadata.
  • Fast, scalable pan and zoom viewing of images with full IIIF Image API support/interoperability.
  • Display of digital objects via the IIIF Presentation API and a wide range of compatible client applications.
  • Cloud storage of collections of images, audio, and video, scalable from the smallest collection to the very largest.
  • Potential integration with digital preservation solutions.
  • Support for annotation of digital content enabling many ways of adding content to digital objects including tagging, transcription, description, classification, and highlighting.
  • Annotation search (with support for the IIIF Content Search API).
  • OCR of typeset/typewritten content.
  • Line-by-line transcriptions generated from OCR/full-text.
  • Full text search (with support for the IIIF Content Search API).
  • PDF and HTML versions of digitised content.
  • Semantic services extracting information about people, places, dates, and other entities, in order to drive search and discovery across content.

Who is the DLCS for?

The DLCS is designed to scale transparently, and seamlessly to any volume of content. Organisations with large collections can use the DLCS to host their content, while small organisations that may not have the infrastructure or resources to host themselves can take advantage of the same best-in-class performance and scalability.

The DLCS is designed from the ground up to be flexible. So, an institution that wants high-performance image delivery for a site they develop and host themselves, but has no need for the other features of the DLCS platform, can do this. Another institution that wants an entire platform providing hosting, discovery, and delivery, in the cloud, could use the full DLCS suite of services to fulfil their needs.

DLCS, IIIF APIs and open standards.

What is IIIF? This acronym (pronounced “triple-eye-eff”) stands for the International Image Interoperability Framework. It is one of the open standards that makes a project like the DLCS possible, because the project can build on existing software, modelling and implementation experience and not start from a blank slate. it also makes it possible for other software to integrate with DLCS provided services without the risk of having to reinvent the wheel, or of being subject to vendor lock-in.

IIIF gives us a model and APIs for providing access to image based material, and for describing and presenting complex objects so that they can be rendered to users in a viewer or other application. If content hosted in the DLCS supports IIIF, any compatible viewer can render them. A IIIF description of an object – e.g. a letter, manuscript, printed book, map, or photograph – also provides us with a model of the object that we can target with annotations at the level of the document, or sets of documents, or individual pages, right down to individual parts of a page . Within a single image (e.g. a page of a letter) a particular paragraph, line of text or phrase can be the target of an annotation, as can a photograph, figure or table. When users or machine-driven natural language processing tools like the DLCS Semantic Extraction Service tag or comment on documents in a web interface, they are creating annotations on the IIIF resources that describe the material. These annotations can be searched, or used to drive a discovery interface, and are also available to all in an open interoperable standard. The core DLCS services support both Open Annotation and the newly emerging W3C Web Annotation standard.

The IIIF Presentation API is the API for humans, which sits alongside any semantic description of the object that exists, such as an archival description or bibliographic record conforming to a common metadata standard. When viewing objects over the web, the IIIF Presentation API mediates for us; it provides the information required for a viewing application to present the material to us. The interoperability guaranteed by support for the IIIF APIs means that such a viewing application could be part of the DLCS platform, or could be hosted anywhere.

Content hosted on the DLCS will automatically be made available via the IIIF Image API, and IIIF Presentation API manifests to drive a viewing experience will be created. IIIF manifests and collections are portable, interoperable formats. People can load DLCS manifests into other viewers, annotate them in other annotation tools and environments, and build new discovery and interpretative experiences from them with no need for those tools to do anything other than support the relevant IIIF and W3C standards.

Read a longer introduction to IIIF here

Hosting and DCLS-as-a-service.

Digirati provide a managed instance of the full DLCS platform on Amazon AWS which organisations can use to host and deliver their content, with all of the services supported by Digirati on their managed platform. However, institutions that wish to have their own dedicated separate managed instance of the DLCS, can engage with Digirati to do so.

All of the core components of the DLCS platform are open sourced with the MIT license, so it is possible for organisations to deploy some or all of the DLCS components independently, and longer term Digirati hope to make easy ‘one-click’ deployment of a full DLCS solution (DLCS-as-a-service) a reality.

Find out more