IIIF (pronounced 'triple - eye- eff') stands for International Image Interoperability Framework. Through a set of international open standards, it enables making cultural and historical heritage digitally more accessible to all in a consistent, collaborative, and seamless manner.
IIIF logo. © International Image Interoperability Framework Consortium.
Picture a scenario in which image-based resources (both static and moving) from collections worldwide share a universal digital language and can be viewed and examined in real-time by anyone with an internet connection anywhere on the planet. Envision a reality where data and images of artworks, manuscripts, newspapers, and countless more objects can be explored, analysed, interacted with, annotated, shared, and reused, seamlessly and down to the smallest detail, regardless of their physical location. IIIF facilitates this and more. It enables organisations to efficiently share high-quality images and detailed data about objects with a global audience, and connects collections spread across the globe.
Origins and Development
A passionate brainchild of expert industry professionals keen to create a way of bringing cultural institutions together and enabling them to share their collections globally, the idea of IIIF originated at a lively dinner of technologists from the Bodleian Libraries at Oxford University, the British Library, and Stanford University Libraries, at a restaurant in California.
Originally recorded on a napkin, thanks to the efforts of an extensive community of software developers, GLAM (Galleries, Libraries, Archives, Museums) professionals; and scholars, it developed to become a major component of how many cultural institutions worldwide interact with and share their collections digitally. In 2015, eleven leading research libraries and nonprofit image repositories formed the International Image Interoperability Framework Consortium (IIIF-C) to enhance global access and interoperability of image-based resources for research and scholarship.
Relevance and impact
Institutions that provide IIIF-based resources can digitally distribute their materials worldwide through IIIF-compatible viewers and tools, providing archives, collections, and other image repositories with an unprecedented opportunity for global reach. By observing the open standards that define the IIIF APIs (Application Programming Interface) developers can establish connections and facilitate communication between multiple platforms and services in different web environments, and even between separate institutions, promoting growing cross-organisational and multidisciplinary collaborations.
How IIIF works
The use of IIIF in GLAM institutions is commonly based on two main open APIs: the Image API and the Presentation API. Like other APIs, they serve as a bridge that enables different software applications to communicate and interact with each other, ensuring smooth interoperability between systems. Although more commonly used with static 2D images, IIIF is also capable of processing and presenting video, 3D, and audio.
Exploring Albert Durer’s A Wise Virgin (recto). Study of a left leg from two viewpoints (verso) (D.1978.PG.251) in IIIF viewer Mirador. The Courtauld, London (Samuel Courtauld Trust), © The Courtauld.
The Image API
Standardises how images are accessed and used online, making it especially useful for institutions like museums, archives, and libraries. It allows end-users to load and view specific parts of an image, and adjust its size, rotation, etc. in a deep-zoom experience. One of its key features is the ability to generate tiles from high-resolution files. These tiles are like puzzle pieces corresponding to the different regions within the image that fit together to form the complete image. This means that instead of loading a large image file all at once, users can seamlessly load smaller sections as they need them. This significantly speeds up the loading time on the web, ensuring a fluid and efficient user experience. Overall, the IIIF Image API promotes consistency, flexibility, fluidity, and compatibility in sharing digital images.
The Presentation API
Standardises how images and their related data are displayed. You will have seen a link named 'Open IIIF manifest' while looking at an object record in The Courtauld Gallery Collection Online. What exactly is a IIIF manifest and what does it do? In simple terms, a IIIF manifest is a unique package of information that brings together descriptive data (metadata) about an object (for example, creator, title, brief description, copyright, etc.) with its image(s) and respective structure (for example a single image of a painting, or multiple pages of a manuscript organised in a specific order).
It is written in a format named JSON,
stored in a server, and accessible via the web. When you open a IIIF manifest
in a web browser you will ‘only’ see a code. By pasting its web address (or URL
- Uniform Resource Locator) into a tool capable of reading and coherently displaying
that code (for example a IIIF
viewer), an end user will be able to see the image(s) and any descriptive information
that the manifest's creator has chosen to display alongside it; all in one place, and
without the need to create new digital copies.
This is the starting point. More advanced features and tools can be added such as annotations, text recognition, search, and more.
Learn more about these and other IIIF APIs.
Layers and tiles: how they work together to deliver IIIF images
IIIF leverages pyramid layers and tiles to provide a seamless and efficient viewing experience.
Consider a pyramid with many levels, each representing the image at a different resolution. The top layer has the smallest size and lowest resolution, while the bottom layer has the greatest size and highest resolution. Each layer is divided into smaller, manageable pieces (tiles) that can be fetched individually as we navigate through the image.
- Initial Load: When you first view an image, the API loads the top layer (lowest resolution) tiles. This gives you a quick overview of the entire image without waiting for the high-resolution data.
- Zooming and Panning: As you zoom in towards the bottom layer and move around the image, the API dynamically and gradually loads tiles from the higher resolution layers. This means you only load the parts of the image you need, reducing data transfer and speeding up the process.
Below is an example that illustrates how this all works. On the left: explore the image (zoom in and out and pan). On the right: observe what layers and tiles you are fetching as you interact with the image.
Visualization of the tile pyramid of a IIIF Image. Made using d3-tile, with d3-zoom. ©Jules Schoonman, Allmaps.
Finding and using IIIF resources
If an organisation shares their collections online using the IIIF standards, you will likely see the IIIF logo and/or links such as 'View/open IIIF manifest' 'Open in IIIF viewer'. Several open-source tools and platforms aim to facilitate the discovery of IIIF resources across collections, such as:
Try it yourself
Although understanding how IIIF works is helpful, the good news is that end-users, such as curators, researchers, teachers, and students, for example, do not need to have technical or coding skills to benefit from it. Why not give it a try?
Open-source viewers
There are multiple IIIF-compliant viewers. Most allow users to pan, zoom, rotate, and resize images. Others have added features, such as search, annotations, etc, and may be more tailored for certain types of content and practical uses, such as comparing multiple images side by side or viewing 3D objects or video. Most viewers can also be embedded in any web page. Paste a IIIF URL into the viewer or use the demo examples, and start exploring.
- Mirador
- Universal Viewer
- Tify
- OpenSeadragon
- Glycerine (Image annotation for research, curation and education)
- Theseus Viewer
Open-source digital storytelling and collaboration
The use of IIIF in digital storytelling, digital displays and other tools for engagement, opens up new possibilities, such as the ability to unite long-lost sections of the same item or artefacts from collections all across the globe; to extend physical exhibitions; and explore and display different facets and interpretations of objects through self-guided and/or oriented virtual narratives.
Inspiring IIIF implementations
- Dessins photographiques sur Papier. Recueil No. 2. [The "Bayard Album"] (The Getty, Los Angeles, USA)
- Digital Mosaic (National Museum of Norway, Oslo)
- Explore the Raphael Cartoons (Victoria and Albert Museum, London, UK)
- Allmaps Arcade (Allmaps)
- Virtual Tour (Kunstmuseum, Basel, Switzerland)
- Shared Heritage collection (Bibliothèque Nationale de France)
- Van Gogh Worldwide (RKD - Netherlands Institute for Art History, Den Haag; Van Gogh Museum, Amsterdam, Kröller-Müller Museum, Otterlo)
- Leonardo//thek@-Codex Atlanticus (Museo Galilieo, Florence, Italy)Sunset Over Sunset (University of Pennsylvania, Swarthmore College, Leventhal Map & Education Center - Boston Public Library, and others, USA)
- Exhibitions on TU Delft Heritage website, (TU Delft Library, The Netherlands)
