International Image Interoperability Framework
The mdwRepository provides an Image Server based on digilib according to International Image Interoperability Framework for the delivery of digital images. For benefits of the IIIF see the official IIIF FAQ.
digilib provides both
- an IIIF Image API (sample image), and
- a IIIF Presentation API (sample manifest.json that contains descriptive metadata about the document presented and technical metadata used for rendering the images)
Please note: The mdwRepository does not provide preservation master images on the IIIF Server for usability reasons but high quality JPEG compressed images.
We use libvips (https://libvips.github.io/libvips/), a fast image processing library that is licensed under the LGPL 2.1+, for preparing the TIF images before delivering them via the IIIF server. The following image conversion call is used:
vips tiffsave input.tif output.tif --compression=jpeg --tile --tile-width=512 --tile-height=512 --pyramid --Q 75
We validate all TIFF images created with JHOVE for technical well-formedness.
At the moment does not use the Jpeg2000 format even though files could be created with ImageMagick via the following command line (for lossless jpeg2000 format):
convert input -quality 0 output.jp2[1024,1024]