Digital Dunhuang: A Standard for Digital Preservation
Peter Zhou
University of California, Berkeley

ABSTRACTThe Digital Dunhuang project is enabling long-term preservationof cultural heritage of inestimable value, while providing aplatform for sharing all digital assets generated in the act ofpreservation. This presentation will examine the major aspects ofdigital asset management and digital preservation implemented inthis ongoing project.

KEYWORDS
Digital preservation, digital asset management, Digital Dunuang,
the preservation of world heritage

1

INTRODUCTION

The Mogao Caves at Dunhuang, a designated UNESCO World
Heritage site, are a splendid treasure house of art from AncientChina. [1–2] The Dunhuang Academy has been devoted to theprotection of the Mogao Caves since its founding in 1944
(originally called the Dunhuang Art Research Institute). The
protection measures include slowing down the degeneration ofmurals with a variety of protecting techniques, as well as looking
for digital tools to preserve the caves since 1990s. The Academy
is currently undertaking the Digital Dunhuang project withcooperation from home and abroad. Work is being done todigitize three-dimensional structures of murals, sculptures and all
the 492 caves, and also to construct a digital database of theMogao Caves resources. The size and scope of the project is quitesignificant. Some exemplary statistics include:[3]•••••Over 100 caves already photographed
Over 14,000 square meters of murals captured
More than 70 terabytes of data
Over 87 caves in complete QuickTime Virtual Reality
Over 20 years of climate monitoring data for 87 caves

The project has called on the expertise of a number of institutions
over the years, including The Dunhuang Academy, Zhejiang
University, Wuhan University, the Getty Conservation Institute,and Northwestern University. It is designed to incorporate a wide
range of data types, including archeological and conservation dataand files, documentation for a large number of artifacts,Dunhuang manuscripts, and scholarly publications.

Figure 1: Digitizing the Dunhuang Caves. Image courtesy ofthe Dunhuang Foundation.

2

FROM DIGITAL ASSET MANAGEMENTTO DIGITAL PRESERVATIONWith the support of The Mellon Foundation, the Dunhuang
Academy has been exploring building a permanent repository ofall digital assets of Digital Dunhuang. It has also made persistentefforts to photograph the caves while conducting archeologicalstudy and conservation work. The Academy has made hugeprogress and accumulated large amounts of data in both analog
and digital formats. The consensus seems to be: if the information
gathered from the Mogao Caves is to be permanently preserved
for future generations, the only way to ensure this is to integrate
all the content that has been created in the past, is being created
now, and will be created in the future into a large digital
repository. [4] This digital repository can facilitate perpetualpreservation, effective digital asset management operations, andeasy access in a systematic way through the use of hightechnology delivery mechanisms. This presentation discusses
major aspects of the design and development of this repository
system. The ultimate goal is to store the totality as well as minutiaof the Dunhuang Caves’ digital content, preserve those digitalsurrogates, reconstructions, files, and digital assets perpetually,and provide a research platform for the study of mural art, history,geography, religion, economics, politics, ethnology, language,literature, science and technology in ancient China and CentralAsia.

conservation data and materials, archaeological reports anddrawings, CAD drawings, and 3D laser point cloud data

2.3 File Formats
TIFF, JPEG, JPEG2000 (still image), PSD, BMP, PSB(Photoshop large file format), CR2 (Canon raw format), DCR(Kodak raw format), DNG (Adobe/universal raw format), otherRAW camera formats (list), CDR (Corel Draw), CAD, PTX(original 3D cloud points), DGN (Microstation Design File), PDF,CAJ, MOV (QTVR), MPEG2/35 Mbps (AVI wrapper), HD videofiles (format TBD), DPG (Ninetendo video file format), Word,Excel, txt, MPEG4, H.264, FLV (Flash)

2.4 Cross-linking
All content (images, documents, etc.) must be displayed withmetadata. For example, an initial search result might display
thumbnails with basic data. The user can then select to see a large
3D image and fuller data.

Figure 2: Dunhuang scientists preparing to digitally scan cavefor 3D modelling. Image courtesy of the Dunhuang Academy.
There is a sense of urgency. More than half a million visitors
come here every year. The historical and cultural significance ofthe caves, as well as their vulnerability- their age, instability of theterrain, and fluctuations of humidity caused by increased humanpresence- all add to the sense of urgency. The digital capture andrestoration of Dunuang will most likely to be the last records oftoday’s Dunhuang.

2.1 Functional Components [5]DAM: Facilitates asset creation, cataloging; image, video, andtext management and delivery and version control. Tracks digitalpreservation actions. Pushes metadata and content to the Digital
Dunhuang platform. Manages master high resolution files andoriginal documents.

Figure 3: An example of 3D rendering of cave interiorpaintings. Image courtesy of the Dunhuang Academy.

3RESULTS AND DISCUSSIONDIGITAL PRESERVATION : Managed digital preservation
actions include creating checksums, validating files, andextracting technical metadata upon ingest; monitoring file format
obsolescence; migrating file formats as well as content; tracking
and copying files to LTO tapes.

Digital Dunhuang is an enterprise project. It enables us to explore
ways to design and develop sophisticated databases, andperpetually preserve massive amounts of data. By extension,
Digital Dunhuang has also shed light on what we need to do topreserve digital assets in libraries and museums around the globe.

PUBLISHNG AND SHARING : Surrogates of master assets
managed in the DAM will be pushed for external delivery.

ACKNOWLEDGMENTS

2.2 Content Categories
Stitched/composite cave images, raw cave images, cave QTVRs,
historical photos, videos, digital restorations, manuscripts from
Cave 17, artifacts (approximately 10,000 objects), reproductions(copies) of images in caves, (digitized) microfilm of manuscripts,
interactive panoramic of caves; research created by members ofthe Dunhuang Academy, scholarly publications; previouslypublished bibliographies, indices, glossaries, and finding aids;

The work discussed was sponsored by the Dunhuang Academy,
with the support from the Mellon Foundation. This presentation
draws on a joint report by Linda Tadic and the author on thefunctional requirements of Digital Dunhuang in 2012; and on apanel discussion at the DH 2015 conference in Sydney, at which
the author discussed this project with other panelists - Wang
Xudong and Wu Jian of the Dunhuang Academy, and J. Stephen
Downie of the University of Illinois. Their contributions aregreatly acknowledged.

REFERENCES[1] Fan Jinshi and Wu Jian. 2004. Dunhuang Grottoes. Beijing: China
Travel and Tourism Press.
[2] Fan Jinshi and Liu Yongzeng. 2007. Appreciation of Dunhuang
Grottoes. Nanjing: Jiangsu Fine Arts Publishing House.
[3] Xudong Wang, Peter Zhou, Eugene Wang, and J. Stephen Downie.
2015. “Digital Dunhuang: Enhancing Virtual Exploration of the RealDunhuang.” Unpublished panel proposal for DH2015 conference, Sydney.
[4] Peter Zhou. 2011. “The Development of a Repository System ofDunhuang Murals and Digital Resources for Dunhuang Studies.”
Proceedings of the International Conference on Cultural Heritage andDigitization, 317–23. Dunhuang: Dunhuang Academy.
[5] Linda Tadic and Peter Zhou. 2012. Digital Dunhuang: A Repository
System of Dunhuang Murals and Digital Resources: Functional
Requirements. Dunhuang: Dunhuang Academy.