The Wellcome Library is building an online resource around the history of medicine, based on its holdings and supplemented with content from other institutions. The long term goal is to digitise the majority of its special collections as well as other types of content. Over time, this will comprise many millions of images (as well as audio, video and born digital files). Increasing digitisation in this way required a rethink of many aspects of the workflow, from choice of equipment to long term preservation of digital assets. This included a reevaluation of our standard preservation image format. Prompted by the high cost of storing TIFFs for such an ambitous digitisation programme, the Library investigated JPEG2000 and found it to be the best fit for both long term preservation and access.
JPEG2000 (or "JP2" as a shorter form, referring to Part 1 of the standard) is not without its issues and difficulties. But with time and persistence the Library is now able to convert and store all its still images, including both the product of on demand photography as well as large scale digitisation projects, as JP2 files. A recent backlog project to convert all the images comprising the Wellcome Images archive (lossless), and all the project images created to date (lossy), saw the storage footprint reduced from 20Tb to 5.5Tb.
The digital library programme is in a pilot stage, which aims to build an infrastructure to make digital content available easily, intuitively, and with a range of features to promote engagement with the content, the Library, and the history of medicine more generally.
For more information on the Wellcome digital library programme, visit the blog.
For more detailed information about JP2 implementation, everything is recorded on our JP2 blog.