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What is IIIF?

What is IIIF and what can it do for you? A guide for everyone who doesn’t speak IT

Mmmonk wants to virtually reunite the monastic libraries of Ten Duinen, Ter Doest, Sint-Pieters and Sint-Baafs on a dedicated online platform. The strategy to achieve this is based on the digital innovation that is IIIF. Rather than gathering digital images from surviving manuscripts, we will gather IIIF manifests of these manuscripts. But what is IIIF?

IIIF stands for the International Image Interoperability Framework. It is a set of open standards that help archives, libraries, and museums host and share digitised collections. IIIF is designed to solve a number of problems encountered by institutions and users alike.

What is the current (problematic) situation? Images of digitised collections are stored in repositories hosted by institutions, and they are made available online on the institution’s bespoke digital collections website. But institutions all over the world use incompatible systems and varying user interfaces (viewers).

For the institution, this means a burden to upkeep the website, the systems and the interfaces. Whenever a system is outdated, the institution faces challenging conversions and data migrations. Institutions might become “hostages” of a system or interface designer, which means they are unable to adopt innovations unless their provider allows it. And last but not least, it is expensive to develop and maintain digital collections websites.

For the end users who want to work with items from different institutions, it means having to cope with varying systems and terms of use.

In response to this, experts created IIIF specifications to provide a standard practice for making digital images and metadata available online, allowing for the transfer and sharing of images and metadata across repositories and systems. IIIF is a protocol, not a software, to be shared and applied as widely as possible.

The main innovation is that the focus has shifted from the image and metadata to a so-called manifest. The manifest, written in a computer script, is a holder for the image and the metadata. It harvests images from a IIIF server or repository and metadata from the institution’s catalogue system. A manifest can be imagined as a frame in which one can slide an image and metadata. The frame can be part of a larger frame. The manifest of a page of a book, for instance, is part of the manifest of a book. Inside the manifest, one can even slide multiple images of the same page, for instance a standard image and a UV light image.

The manifest is stable, with a persistent URL. So should an institution in the future decide to use newer, higher quality images, they will simply add the new images to their respective manifests, and this will not affect the URL. The manifest is also interoperable, written in a json script, which means it can easily be shared and used in a wide variety of applications and environments.

The IIIF community also developed IIIF viewers. The most prominent to date are Mirador and Universal Viewer. Instead of looking at images on various institutions’ websites, and switching back and forth between special collections websites, one can open images from various collections into one single viewing interface. Paste a IIIF manifest for a manuscript in Paris into the viewer, and it appears. Then next to it, add a IIIF manifest for a manuscript in Ghent. Both manuscripts are shown in the same environment, side by side, facilitating research and comparison. The manifests can be found in the records of the items in the institution’s catalogue (if they are IIIF compliant), simply look for the red and blue IIIF logo in the item’s record.

Apart from the obvious benefit of a single viewing environment across the boundaries of institutions, IIIF offers a number of other major benefits for end users: the images are delivered almost instantly, even when they are high resolution, and size, scale, region of interest, rotation, quality and format can be manipulated. Last but not least, IIIF allows users to comment on, transcribe, and draw on image-based resources.

Users who want to use an image for their own website or project, no longer need to download the image, host it on their own server and upload it to their website. They can simply embed the manifest (URL) or convert it into a IIIF jpg. For a guide on how to do this, visit The image shown on an independent website will always refer back to the same, single copy hosted by the institution. And at a click on the embedded image, the image will be opened in its specific context. Click on a detail from a miniature, for instance, and you will be taken to the images not only of the complete folio on which the miniature appears, but of the whole manuscript.

And finally, IIIF is also an active community of developers and users, who host an interesting website with everything you want to know about IIIF:

(Evelien Hauwaerts, 2021, for Mmmonk)

The situation now is often like this: institutions use isolated systems for digital images and metadata. They store the data on local servers, manage the data in local systems and catalogues, and show them to the public on local websites.

There are a lot of problems with this situation.

  • The data is isolated and there are borders between institutions and collections.
  • It’s expensive for institutions, because the systems are customized and every upgrade costs a lot of money (vendor lock-in syndrome).
  • And for end-users it is complicated, for instance, when you’re working with items from five institutions you’ll probably have to use five different web pages at the same time, all with different types of viewers, interfaces, functionalities, etc. This can be frustrating and time-consuming for the end-user.

How does IIIF solve this? IIIF takes the images and metadata and pulls them out of their isolated silos.

IIIF wraps the data in a uniform packaging written in a computer language: json.

The packaging is called a manifest.

The json code follows a set of standards that is internationally agreed upon by everyone in the IIIF community, so it is uniform and universally readable by computers and humans.

With this manifest, we can pull the images and metadata out of their isolated systems.

The IIIF community has developed free tools and applications for these IIIF items, like viewers, and tools to build virtual exhibitions.

You can pull images and descriptions from Ghent, Cambridge, Paris, Chicago… and combine them in one single IIIF viewer or in a IIIF virtual exhibition.

So IIIF makes the data interoperable, it frees the data from their isolated silos.

Another benefit of IIIF is that it can help to reduce the carbon footprint of working with digital images, because it can help us to avoid unnecessary downloads which require extra energy from servers.