The Seeing the Dead project's Work Package 2 - Visualising the Dead will see Heritage360 undertake precise 3D scans of the project's primary focus: the gypsum casts held by the York Museums Trust (YMT) and other partner organisations. The scans will provide highly detailed digital models of the casts' surfaces, capturing the outline form of buried individuals, fine details of textile imprints, plus many other elements that are often not visible to the human eye.
In April 2025, one of the first key Seeing the Dead tasks was to 3D scan the gypsum burial casts held at the YMT stores in York. In this blog piece, we'll explore the technology used to capture these digital models and see how they will inform research in the project's other work packages.
How does the technology work?
Heritage360 uses two types of 3D scanner: the Artec Leo and the Artec Space Spider. Both are light-weight, hand-held devices that can be easily manoeuvred to capture complex surfaces. Importantly, the scanners capture data at an extraordinary precision of as little as 0.05mm - roughly the width of a human hair! This means that fine details imprinted in the surface of the gypsum while it was still wet can be identified, including textile fibres, wood grain or even fingerprints.
But how does it work? Both scanners utilise a technology known as 'structured light', which involves projecting striped pulses of light onto a surface. A perfectly flat surface will simply retain the straight edges of the light stripes, but any bumps or crevices in a surface will distort the light - something that the scanners' sensors can detect at incredibly fine resolutions. If you wish to know more, read Artec's How does structured-light 3D scanning work? for some fascinating extra detail!
We can use our scanners to capture objects from around 3cm in size to as large as several metres. This allows us to work with small finds from archaeological sites and museum collections, through to architectural features in cathedrals and other historic properties. The 3D scanners are also able to work with a wide range of materials, including stone, metals, wood and many man-made substances - although highly shiny, transparent or translucent materials (e.g. glass) are still difficult to capture.
Fortunately, the gypsum casts on the Seeing the Dead project are almost perfect for scanning! Most are of a size that can be moved by hand to allow capture of both the front and back surfaces, whilst the gypsum material itself has proved to have a texture very well-suited to structured-light scanning.
How do we undertake the scans?
3D scanning can be a very quick, efficient method of digital capture, and we would typically aim to scan an object of around 50cm x 50cm in a matter of minutes. However, every environment is slightly different and before scanning can commence we need to undertake a number of important steps:
- Create a working area. Although scanning is undertaken 'up close', we still need an area to manoeuvre both the objects and ourselves safely. The YMT stores presented a tight area in which to work, but we created a working area with (just!) enough space to move the larger gypsum casts, and which also included a table to ensure the lighter pieces could be scanned at a comfortable height and could be easily turned to capture all surfaces.
- Controlled light. The scanners work best in environments where there is a good amount of even, consistent light. Scanning outdoors on days where the sun is in and out of cloud is therefore very difficult! However, we were able to control light levels at the YMT stores using two high-powered stand lights that could be directed onto significant areas.
- Health and safety. Every scanning job is slightly different with regard to health and safety, and at the YMT stores our primary concerns centered around the tight working space and the potential trip-hazards presented by the large number of wires to laptops, lights, etc. As always, we also needed to be aware of any photo-sensitivity in other team members that may be triggered by the scanners' flashing light pulses.
Once the points above were addressed, the scanning could commence! By moving the scanner's sensors over a surface in a smooth, regular fashion, a digital model can be quickly built up. In many cases we can easily stop and then restart scanning - the already-captured surface topography will be recognised and the scanner will pick up from where it left off. However, most gypsum fragments needed to be turned over to capture the reverse side, so two or more separate scans were taken and digitally 'stitched' together as part of the data processing stage (see below).
A wonderful feature of both scanners is the ability to see the model on-screen as it's created, allowing the team to see the fascinating features emerging in real-time. Once a scan has been captured, it can be reviewed and any 'gaps' or areas of poorer data are re-scanned.
Processing and outputting the scans
The scanning at the YMT stores took place across two days, and over 40 individual fragments were captured from nine distinct burials. But the work didn't stop there - the scanned data needed to be processed and then output into an accessible form for use by the project's other research teams.
Processing scanned data can sometimes be a time-consuming task. Any imperfections or unnecessary data needs to be removed, while objects that were captured across multiple scans (e.g. a front and back) need to be 'stitched' together within the Artec Studio software that receives the data from the scanners.
Another important part of the process is to 'invert' the captured scan data. The gypsum casts represent the 'negative' imprints of bodies and objects encased by the gypsum, but by essentially turning this data 'upside down' we are able to present these negative impressions as 'positive' raised features that are much easier to interpret.
Once complete, the models are typically exported to an online viewer such as Sketchfab for circulation amongst the project team. Here are a couple of examples:
Supporting project research
The 3D scans captured at the YMT stores - and those yet to be captured at other locations - will form a vital source of data for the Seeing the Dead project's research teams over the coming years. Physical access to these large, and often quite delicate, objects is understandably limited, so the digital scans present a high-quality, accessible alternative for our researchers. Several key aspects can be examined using the scans:
- The outline and form of buried individuals. By examining the shapes left by the buried individuals, we may be able to infer their age and sex, and perhaps even gain insight into conditions such as malnourishment or physical disabilities.
- Textiles / wrappings. Individuals were often wrapped in textile shrouds before burial. The 3D scans clearly show the folds and creases of the burial textiles against the wet gypsum, while in some cases even the fine weave of individual fibres can still be seen!
- Objects. Roman burials often included objects - or 'grave goods' - that were buried with individuals. The 3D scans have already suggested the presence of shoes within the burial, while further research will hopefully identify other mysterious shapes visible within the dried gypsum casts.
This data will also be augmented by CT scanning technology (Work Package 4 - Items within the gypsum casings), which will go beyond the surface scanning undertaken here to see inside the gypsum.
As research progresses, we'll publish more material about the scans and the research they support - keep checking back!