IRP Showcase: Super-sized images

In this article we want to show off the IRP image viewer and explore some of its capabilities. First we need to answer one very important question - what is a super-sized image? There is no official definition, and such a definition would have to change regularly as technology changes. Large images from twenty years ago are now considered to be only slightly bigger than thumbnails! It is worth nothing that many organisations classify their images by the pixel size of the image, making some arbitrary decision about what medium and large mean. Some talk about resolution, but without regard to the original object. However, the resolution of a 1024 pixel wide image for an object of 1mm wide, is quite different from 1024px image of an object 1m wide! Whenever we talk about resolution it really needs to be in terms of pixels/cm of the original source. For this article, we aren't looking at resolution per se but image size. Any image 50 megapixels and over will be considered to be super-sized.

Digital imaging technology is advancing rapidly. As of March 2021, mobile phones support 10-40 megapixel cameras and digital SLRs offer 30-50 megapixels. Although the demands of iconography research are significant, a sharp close-up at a lower resolution can yield as much information as a wider image at higher resolution. However, it is nice to be able to view an entire work and then just keep zooming in on the details.

The IRP supports both multiple images for a source and deep-zooming to efficiently view an image of any size. The images are stored as pyramid tiled TIFFs (we can use BigTIFF as well). TIFF image files can be up to 4 gigabytes in size, and BigTIFF up to 18 exabytes. Currently the largest image in the BSIP database has a file size of 1.1GB and that supports an image of 965 megapixels (just under 1 gigapixel!). A standard TIFF file can therefore support an image of around 3.5-4 gigapixels depending on the compression achieved. We haven't worked out how big a BigTIFF image can support, suffice to say, huge!

In the BSIP database, 10% of the images are over 20 megapixels, and only 1% are over 50 megapixels. This highlights how digital image availability is lacking behind capabilities by quite a long way. The good news is that the future will see more higher resolution images yielding increasing levels of details. The BSIP IRP has been designed and engineered for the future - we are ready and waiting and no image is too big!

Enough tech chat! Let's take a look at some great images!

Below are three sources that have images that show off the IRP Source Image Viewer's deep-zooming capabilities. After navigating to the sources we recommend turning off the pins and pulses and placing the image viewer panel itself in full screen mode for maximum enjoyment!