Practical application of visible-induced luminescence and use of parasitic IR reflectance as relative spatial reference in Egyptian artifacts
Egyptian blue (CaCuSi4O10) is one of the most ancient artificial pigments, widely used in ancient times. Its peculiarity is an exceptional infrared emission upon visible excitation, allowing an easy and non-invasive diagnostic through the so-called visible-induced luminescence (VIL) technique. Usually, it requires total absence of infrared parasitic light, highlighting areas in which the pigment is present even in traces. In this report, we propose the introduction of a small portion of IR parasitic light as spatial reference for locating Egyptian blue on analyzed object. In VIL modality, the contemporary reflectance transformation imaging (RTI) and 3D photogrammetric model reconstruction were performed with the final 3D rebuilding of surface, morphology, and pigment distribution. We demonstrated the possibility to perform VIL and 3D photogrammetry without opening the conservation case that is extremely important by a conservation point of view, avoiding any microclimatic alteration, compatibly with the minimum invasiveness (absence of contact and displacement of the object).
KeywordsEgyptian blue Visible-induced luminescence Infrared emission Reflectance transformation imaging Photogrammetry Egyptian artifacts
The authors kindly acknowledge Dr.ssa Valentina Turina of the Museo Egizio di Torino (Fondazione Museo delle Antichità Egizie di Torino, Turin, Italy) and Dr. Guido Rossi of the Museo di Archeologia Ligure (Genoa, Italy) for having granted analyses on the artifacts.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Accorsi G, Verri G, Bolognesi M, Armaroli N, Clementi C, Miliani C, Romani A (2009) The exceptional near-infrared luminescence properties of cuprorivaite (Egyptian blue). Chem Commun:3392–3394. https://doi.org/10.1039/b902563d
- Ajo D, Chiari G, De Zuane F, Favaro ML, Bertolin M (1996) Photoluminescence of some blue natural pigments and related synthetic materials. In: V Internat. Conf. Non-Destructive Testing, Microanal. Methods and Environm. Eval. for Study and Conservation of Works of Art (Budapest, September 24–28, 1996). Proceedings, 33–47Google Scholar
- Alfeld M, Baraldi C, Gamberini MC, Walter P (2018) Investigation of the pigment use in the Tomb of the Reliefs and other tombs in the Etruscan Banditaccia Necropolis. X-Ray Spectrom:1–12. https://doi.org/10.1002/xrs.2951
- Berke H (2002) Chemistry in ancient times: the development of blue and purple pigments. Angew Chem Int Ed 41:2483–2487. https://doi.org/10.1002/1521-3773(20020715)41:14<2483::AID-ANIE2483>3.0.CO;2-U CrossRefGoogle Scholar
- Cortese V, Rossi G (2008) Dalla terra nera alla terra di Ponente. La collezione egizia del Museo di archeologia ligure. Il portolano, Genoa. ISBN-10: 8895051068Google Scholar
- Cultural Heritage Imaging (CHI) (2018) Reflectance transformation imaging. Guide to RTIViewer. Cultural Heritage Ima- ging and Visual Computing Lab, ISTI-Italian National Research Council, San Francisco, CA http://culturalheritageimaging.org/downloads/. Accessed January 2019
- Malzbender T, Gelb D, Wolters H (2001) Polynomial texture maps. Proc. 28th Annu. Conf. Comput. Graph. Interact. Tech. - SIGGRAPH ‘01 519–528. https://doi.org/10.1145/383259.383320
- Mateos LD, Cosano D, Esquivel D, Osuna S, Jiménez-Sanchidrián C, Ruiz JR (2018) Use of Raman microspectroscopy to characterize wallpaintings in Cerro de las Cabezas and the Roman villa of Priego de Cordoba (Spain). Vib Spectrosc 96:143–149. https://doi.org/10.1016/j.vibspec.2018.04.004 CrossRefGoogle Scholar
- Miriello D, Bloise A, Crisci G, De Luca R, De Nigris B, Martellone A, Osanna M, Pace R, Pecci A, Ruggieri N (2018) Non-destructive multi-analytical approach to study the pigments of wall painting fragments reused in mortars from the archaeological site of Pompeii (Italy). Minerals 8:134. https://doi.org/10.3390/min8040134 CrossRefGoogle Scholar
- Mytum H, Peterson JR (2018) The application of reflectance transformation imaging (RTI) in historical archaeology. Hist Archaeol 52:489–503. https://doi.org/10.1007/s41636-018-0107-x
- Verri G, Saunders D, Ambers J, Sweek T (2010) Digital maping of Egyptian blue : conservation implications. Stud Conserv 55:220–224. https://doi.org/10.1179/sic.2010.55.Supplement-2.220 CrossRefGoogle Scholar