3D Imaging Technology:
A look at current applications in the field of cultural heritage preservation
As 3D imaging becomes more ubiquitous, its applications in cultural heritage preservation continue to proliferate. While 3D imaging does not replace other preservation technologies and techniques completely, it provides new possibilities. Not only can 3D imaging aid in documentation, research and replication for professional use, but it also creates new educational opportunities for the patrons of cultural heritage institutions. According to Wahiowiak & Karas (2009), “In a North American context, 3D scanning of cultural material continues to be new and largely uncharted territory”; however, “the success of 3D scanning projects has resulted in the recent expansion of commercial 3D technology designed with an eye to heritage applications” (p. 143). This makes it an exciting and largely experimental time for cultural heritage institutions, who are now discovering the limits and capabilities of this technology.
Limitations of the Technology:
As with any technology, 3D imaging has its limitations. One that is very often mentioned is color. While many scanners can sense the color of the original, placement of that color within the image is done manually. A common technique used to increase the accuracy of the scanned 3D image is called “texture mapping.” Software creates a pattern of colors from scanned images, and a specialist must map out the pattern, like wrapping a thin piece of fabric over each crevice and deviation. (Wachiowiak & Karas, 2009, p. 156) Additionally, a 3D printed replica will not contain the colors of the original object, but the resin in which it was made. According to Dr. Charlotte Brassey, who worked on the Stegosaurus project previously mentioned, “There were a surprising amount of meetings to decide on that color (of the Stegosaurus replica bones)” (Crouse, 2015). They decided on red, since trying to mimic the color of the original bones created a strange effect, and might make patrons think the replicas were real and discourage them from touching–or worse, convince thieves that the pieces were valuable.
Another example of the technology’s limitations is cost. While the overall cost of creating these replicas can be much less expensive and time-consuming than creating molds and castings, the initial cost is high. The machines themselves, even on the affordable end, cost $100,000 to $200,000, and the software must often be purchased by a third party and is usually very expensive. Additionally, the hardware used in conjunction with this software must be top-of-the-line to really receive the best benefits of the technology. Another cost is the material used in 3D printing. There are a variety of materials that may be used, but the stability and long-term life of those materials varies. Materials expected to last and hold up against use for an extended period can be very costly.
Perhaps the biggest issue to cultural heritage institutions, 3D imaging technology is currently not sophisticated enough to create exact replicas for the purposes of preservation. Images and replicas may be used in place of the originals to educate and study, but they cannot replace the original. This includes color, but also, large and complex objects can be difficult to accurately recreate, both in scale and resolution. When the original object has numerous cracks, bumps, chips and other abnormal deviations, the data set becomes too complex and the system will often compress the data to make it more intelligible. This means that the 3D image will not contain the detail of the original, and will appear smoother. For proper documentation, as with the waterlogged wooden objects in Italy, resolution is crucial. As is pointed out in the same study by Bandiera, Alfonso & Auriemma (2015), “3D imaging does not provide a complete picture” (p. 21).
In regard to 3D imaging for preservation, “the scan is probably a far better archival resource” (Wachiowiak & Karas, 2009, p. 147). However, this still means contending with all the same issues faced by digital preservationists: organization, documentation, metadata, and the eventual need to convert old formats as technologies change and evolve. Cokie Anderson (2005) also lists “file format, storage media, technology infrastructure (including security), organization stability, financial stability, and administration and accountability” (p. 9). Whether cultural heritage institutions will slowly begin to convert previous documentation created by cameras into 3D graphic images remains to be seen. Regardless, it would be a huge undertaking–one that, once started, may remain incomplete by the time the next new technology appears. There are certainly some objects better suited to overhead scanners or digital cameras–most notably books, manuscripts and other paper documents. Perhaps, then, the best option would be not to utilize 3D imaging as a replacement for previous digital methods of preservation, but as a supplement where those methods fail or fall short.
Even considering its present limitations, 3D imaging technology is changing the landscape of cultural heritage preservation. Institutions now have 3D graphic models which they can study and share with other institutions across the globe. 3D replicas are now possible without the use of destructive modeling and casting. These replicas can be utilized in ways the actual, fragile originals could not be, both in tests for further study and in education. The ability to touch and examine these models is creating a new, enriched experience for patrons–including patrons who were previously not able to share as fully in the institution’s offerings. It is likely that as these technologies are further explored and studied, new applications will continue to arise. According to Wachiowiak & Karas (2009), “the opportunity to influence the use and development of this remarkable technology is at hand” (p. 157).
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