In a previous post I discussed the mobile-GIS survey during the 2017 season at the Hatnub travertine quarries. During the same period, I also undertook reflectance transformation imaging (RTI) of specific inscriptions.

Reflectance Transformation Imaging (RTI)

Along the descending passage into Quarry P are a number of flat panels carved into the rock and originally containing inscriptions left by the expeditions to the quarry. Most of these inscriptions were copied by Georg Moeller and published after his death by Anthes (1927). The current Hatnub Project has been able to locate most of the inscriptions, refine our understanding of the originals and add several new examples to the total. During the September 2017 field season, I spent a week recording three of these inscriptions in situ in the quarry using Reflectance Transformation Imaging (RTI) to reveal elements of these inscriptions that are not normally visible.

Reflectance Transformation Imaging (RTI) is a digital photographic technique originally invented by  Tom Malzbender and Dan Gelb of Hewlett-Packard Labs, that reveals the surface texture of an object or inscription in great detail, making it possible to identify surface features, inscribed imagery and incised inscriptions that are not visible under normal conditions. RTI software uses a series of photographs taken from the same position and artificially lit by a flashlight situated the same distance from the artefact but at different directions and angles to it. By synthesising the changing interplay of light and shadow from these photographs, the software is able to determine the angles of the surface of the object and RTI viewing software is then able to recreate the image as lit interactively from any angle.  More information about the origin and nature of RTI, and instructions on how to view or create RTI imagery are available from the CHI website.

The results of the RTI were useful and demonstrated the potential of this technique at the site. The RTI revealed that a curious inscription (Anthes VII) included a figure of a seated king to the left of the serekh, despite considerable damage in this area. Further down the descending passage, into Quarry P, RTI of a carved hieratic inscription (not been published by Anthes and designated DS14 by the Hatnub Project) revealed the seated figure carved to left was sitting on a low chair and clarified the hieratic text to the right of him. Inscription Anthes XI z on Little Man Boulder, is in very finely incised hieratic and was almost impossible to read up to now. I recorded this in three parts and we have now been able to read a number of the sign groups using RTI to alter the direction of the light and bring out the precise form of the hieratic signs.

In addition to the three in situ inscriptions, I also undertook RTI imaging on a small freestanding stela (HP5) found in the trench in Zone 3 below the many red ink graffiti on the southern wall of the Quarry circle. Because this stela was freestanding it was possible to undertake the RTI in  the dig house, providing more controlled conditions. The RTI capture confirmed that the stela shows a partly incised figure of a man, but did not reveal much more.

Conclusion

The strong Egyptian sun proved difficult to overcome. RTI requires the filtering out of all natural light, and once our filters were strong enough to eliminate the sunlight, the speed-light we used to light the reliefs struggled to produce enough light for the camera at some points. A larger studio flash would likely overcome this problem but would necessitate the purchase and transport of such large equipment to the site. The newness of RTI also proved difficult in terms of methods for extraction and publication. The results are viewed through the RTI viewer, but extracting them in a format suitable for publication or collaboration with other authors is not straightforward. Static images do not convey the dynamism of the moving light and if linguists and other collaborators do not use the RTI viewer themselves, viewing and checking the RTI results as research continues can be difficult and clunky. The prevalence of zoom technology since the COVID-19 pandemic should simplify collaborative research of this nature and new technical developments may resolve some of the issues of how to represent RTI results for publication. Nevertheless, the 2017 research demonstrated that RTI can contribute to improved legibility of incised reliefs at sites like Hatnub and it would be beneficial to return to the site with better equipment in the future.

Acknowledgements

I am grateful to the Egyptian Ministry of Antiquities for permitting and facilitating the work at Hatnub. I particularly wish to thank Mr. Mohammed Khallaf, director of the Middle Egypt at the office for antiquities in Miniah, represented by Mahmoud Salah, director of Miniah at the office for antiquities in Miniah, Mr. Hamada M. Abdel Moeen Kellawy, and Mr. Mohammed Khalil Mohammed Khalil, our MSA inspector for his support and his work during the fieldwork at Hatnub. The author is also grateful to Yannis Gourdon and the Institut Français d’Archéologie Orientale, our collaborators on the Hatnub Project

The 2017 fieldwork was funded by the Egypt Exploration Society. Additional funding for the IFAO and University of Liverpool fieldwork at Hatnub Project came from IFAO, the British Academy, Fondation Kheops, Gedeon and the BBC.

I also wish to thank Kathryn Piquette for her invaluable training on RTI in 2017.