IIIF stands for International Image Interoperability Framework and is a standard to deliver images over the web and has existed since 2011. Normally, a website operator embeds an image in a website, which is then downloaded and displayed for visitors in their browsers. The vast majority of images that can be seen on the web is delivered from web servers to users in this fashion. Simple.
IIIF is a more involved way to deliver images. On the server side, it requires not only a web server, but an image server. On the user side, it not only requires a browser, but an IIIF viewer. So, why would anyone go through the hassle of inventing this standard, inventing image servers, and inventing IIIF viewers?
Left: Viewing a high resolution image with an IIIF viewer: zooming an panning is easy to do. The example source is: Selden Map of China, 1620–1629, Bodleian Library MS.Selden supra 105, Photo: Bodleian Libraries, University of Oxford, Link
Right: Viewing a high resolution image in your browser is a pain, as it is not optimised for zooming an panning on big images. The example source is the same as on the left.
There are some very practical benefits to delivering images conforming to the IIIF standard:
- Imagine you are viewing a very big image, say a 10,000×10,000 pixel scan of an oil painting. This is annoying to do through your browser: it takes a long time to download, and panning around the image is a pain. An IIIF viewer first shows a low-resolution version of the image, and only increases the resolution as the user zooms into the picture. This way, the user does not have to download the whole picture at once. Furthermore, the IIIF viewer is made to give the user a cozy zooming/panning experience.
- Imagine you are a museum and want to share images together with didactics and annotations online. Of course, you are free to do so, using your own HTML code. But IIIF defines a standard to write down those didactics and annotations, which will then be conveniently displayed in any IIIF viewer alongside the images. So, IIIF is a convenient way for website owners to display content without having to do any development themselves.
An example of an IIIF image with annotations, displayed using digilib. It can be accessed here. Source of the image is: Cunard Line – to all parts of the world, poster, Ulrich Gutersohn, about 1920, England. Museum no. E.1829-2004. © Victoria and Albert Museum, London
Now, of course, whenever anyone defines a standard, they have much higher goals than catering to the laziness of website operators or website visitors. Here are two more philosophical reasons why IIIF was brought into life, and the reader may judge by themselves how realistic these scenarios are:
- If every website has their own way to display images with didactics and annotation, I am bound to find one way that I don’t like. If the websites instead provide their images according to the IIIF standard, I can consume them using my favourite IIIF viewer.
- Different institutions may hold different parts of a collection, or even different parts of a single work (here is an article about the latter scenario: https://www.newyorker.com/business/currency/scattered-leaves). In a pre-IIIF world it would be a headache for any of these institutions to provide their users with a way to view the thing as a whole. However, if every institution delivers their part of the work via IIIF, then anyone can just collect all the image links, add annotations and didactics as they please, and create a continuous viewing experience.
So, here are two ways how you can join the IIIF fun as a user:
- Visit a website that has an embedded IIIF viewer. For example, check out this ornate map of shipping routes from 1620s on University of Oxford website, or this Harvard website having embedded the Mirador viewer to display a manuscript.
- Take your favourite IIIF viewer and view IIIF content in there. For example, here you can view the map from the previous point in UniversalViewer, another IIIF viewer.
The coming two parts will teach you how to impress your website visitors by delivering your very own IIIF pictures to them.
示例來源：Selden中國地圖，1620–1629年，MS.Selden supra 105，照片來源：牛津大學Bodleian圖書館（鏈接）
以digilib瀏覽器展示帶註釋的IIIF圖像（ 鏈接）。 圖像來源：Cunard Line – to all parts of the world，海報， Ulrich Gutersohn，約1920年，英格蘭。 博物館編號 E.1829-2004。 ©倫敦維多利亞和阿爾伯特博物館
4. 一套館藏，甚至一件藏品的不同部分可能分散在不同的機構（後一種情況可閱：https：//www.newyorker.com/business/currency/scattered-leaves）。 在IIIF未被發明之前的世界，這些機構是很難讓讀者了解館藏的完整度的。 但是，如果它們都支援IIIF技術，那麼任何人只要取得所有圖像的鏈結，便可在同一圖像瀏覽器觀看和比較圖像，更能在閱時添加註釋，讀者便能享有一個完整的瀏覽體驗。