Examination, Conservation and Analysis of a Gilded Egyptian Bronze Osiris

See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/262956942 Examination, conservation and analysis of a gilded Egyptian bronze Osiris Article in Journal of Cultural Heritage · October 2002 Impact Factor: 1.57 · DOI: 10.1016/S1296-2074(02)01238-4 CITATIONS READS 13 78 2 authors, including: Lynn Swartz Dodd University of Southern California 24 PUBLICATIONS 69 CITATIONS SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, Available from: Lynn Swartz Dodd letting you access and read them immediately. Retrieved on: 13 April 2016 Journal of Cultural Heritage 3 (2002) 333–345 www.elsevier.com/locate/culher Examination, conservation and analysis of a gilded Egyptian bronze Osiris David A. Scott a,*, Lynn Swartz Dodd b aThe Getty Conservation Institute, Museum Research Laboratory, 1200 Getty Center Drive, Los Angeles, CA, 90049 - 1684, USA bUniversity of Southern California, Taper Hall of the Humanities, 328 MCO 355, Archaeological Research Collection, Los Angeles, CA, 90089-0355, USA Abstract A heavily corroded Egyptian bronze figurine of the god Osiris was examined and shown to have been originally gilt with gold leaf and inlaid with blue glass. Detailed formal comparison between this Osiris figure and the known corpus of bronze and stone sculpture leads to the inference that the statuette dates to the time between the Third Intermediate Period and the fourth century BC, with a greater probability of originating from the Third Intermediate Period through to the 26th Dynasty, or even possibly as late as the fourth century on the basis of stylistic similarities. An extensive corrosion crust of atacamite and chalconatronite completely obscures inlaid glass decoration, found during the investigation, together with remnants of a gilded surface. Analysis of the glass by electron microprobe showed a composition consistent with early Egyptian blue glass with high sodium oxide and low potassium oxide content. The solid cast bronze is a leaded tin bronze, and the gold is a gold foil applied to the bronze surface, originally alternating in decoration with the blue glass. The chalconatronite and atacamite patina appear to be closely associated in the development of the unusual but extensive chalconatronite crust that now covers part of the surface, as a natural corrosion process in this case, not derived from subsequent conservation treatment. The loss of the light blue corrosion crust was prevented by consolidation with Paraloid B72, as examination over several months showed no sign of continued chemical instability. © 2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved. 1. Research aims 2. Description The purpose of the present paper is to undertake a The bronze Osiris now appears completely covered in a detailed scientific investigation of the corrosive deteriora- thick, green corrosion crust with lighter blue patches. The tion and morphological characteristics of an Egyptian principally verdant colour of the once-gilded God is quite bronze Osiris in the Archaeological Research Collection of appropriate for his symbolism as a god of regeneration in the School of Religion, University of Southern California the afterlife. The Papyrus of Ani from 1250 BC in the (USC 5047). The bronze appears to be actively corroding British Museum [1] illustrates a green Osiris, enthroned, with the continual loss of small fragments of light blue sitting in judgement over the dead. However appropriate corrosion from the heavily mineralized surface. As the this modern colour may be, this Osiris figure would not have bronze is of unknown provenience, it is also important to appeared green originally. This figurine was gilded and evaluate the technical art historical background of the details of the beard and royal insignia were highlighted with Osiris, which is shown in Figs. 1 and 2, with some detail of inset blue glass, as reconstructed in Fig. 5. The eyebrows the remaining gilding and a closer view of part of the may also have been inlaid. The Osiris figurine is, as usual, corrosion crust in Figs. 3 and 4. The requirements for depicted with his arms and legs bound to his body by conservation of the bronze are also assessed in the context mummy bandages. Osiris is customarily shown mummi- of this research. form, and when colour is indicated, he is seen wrapped in white cloth as would have been the case when a body was prepared for burial during mummification. The bronze figure shown here holds the crook and the flail, symbols of royalty, and also wears the white crown of Upper Egypt, the * Corresponding author. E-mail address: [email protected] (D. Scott). southern portion of the country. Visual examination does not © 2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved. PII:S1296-2074(02)01238-4 334 D. Scott, L. Dodd / Journal of Cultural Heritage 3 (2002) 333–345 Fig. 1. Gilded bronze Osiris (USC 5047) from the collections of the University of Southern California. Frontal view. Copyright Bruce Zucker- man, West Semitic Research Collection. Scale in cm. Height 255.1 mm. reveal any difference in the corrosion on the sides of the crown, where fittings for feathers might have been attached, and so we assume that the crown was simply the White Crown and that no atef feathers were affixed in antiquity. Had the gilding of this ancient bronze Osiris figurine remained intact, he would have been entirely gilded (with blue inlay) as an example from the Bastis collection, shown in Fig. 6 illustrates. The ancient Egyptians referred to the flesh of their gods as gold, cf. The Destruction of Mankind/Myth of the Heavenly Cow: Haw = f m nbw “…his Fig. 2. Gilded bronze Osiris (USC 5047) from the collections of the body (was) as/like gold...” [2]. Gilding was used not only on University of Southern California. Side view. Copyright Bruce Zuckerman, metal but also on wood as examples from the Brooklyn West Semitic Research Collection. Scale in cm. Height 255.1 mm. Museum and the Pelizaeus-Museum, Hildesheim ([3], Fig. 68) illustrate. Gilding may have been used to create contrast detached flakes within the voluminous corrosion crust. This with the bronze material that might have had a duller glow corrosion crust is primarily a thick, dark green, mineralized than the gold in its original cast state, or may have been layer incorporating rounded quartz grains on the exterior polished to a high sheen as was the case with mirrors, or surface, together with chalky-blue patches of corrosion that special alloys may have been subjected to a surface treat- protrude beyond the dark green patina. ment, producing “black bronze”. Many objects are not During exploratory mechanical cleaning of a small re- entirely gilt, instead the gold is used as a partial decoration, gion of the surface near the folded arms, we found the leaving other parts of the surface free for glass inlay or remains of blue glass inlay that were buried beneath the chasing [4]. thick green corrosion crust. Following this discovery, care- Figure 4 shows that the gilding is especially well ful examination showed that the blue glass is part of the preserved between the crossed arms and is present as original decoration of the arms and also occurs in the beard. D. Scott, L. Dodd / Journal of Cultural Heritage 3 (2002) 333–345 335 Fig. 5. Gilded bronze Osiris (USC 5047) reconstruction sketch of left side profile and front. Drawing not to scale: left profile approximately same as Fig. 3. Gilded bronze Osiris (USC 5047) View of the back with extensive object. alteration to chalconatronite at the base and at the shoulders. Scale in cm. investigative cleaning in search of further remnants of glass There are instances of white (travertine limestone) and inlays would damage the object so that it is difficult to say black (copper-rich metal) inlays ([5], plate 25; §206f) used with surety whether the eyebrows were once inlaid. It is in the decoration of Osiris’s crook and flail and rarely red or very likely that the now-vacant eyes were once inlaid and green inlays ([3], fig 78) are found; the preserved glass on they may also have been lined with blue glass or black inlay. the USC Osiris is uniformly blue. Glass still remains in the The dark green corrosion crust, overlying cuprite, is beard and in the crook and flail. The eyebrows were incised cracked in many areas of the surface, revealing further green but the area is now so corroded and fragile that any layers, approximately 1.5 mm below, and with cuprite below that. The fissures that have opened up in this dark green layer suggest periodic hydration and dehydration of Fig. 4. Detailed view of the region between the crossed arms which retains remnants of the gilded surface. Part of the corrosion crust can be seen which comprises dark green atacamite and light blue chalconatronite, with Fig. 6. Osiris. Bronze fragment of head with inlaid eyes. Height 4.2 cm, occasional cuprite pustules, which have formed over the atacamite and width 4.0 cm and depth 2.4 cm. Stylistically and technically dated to the chalconatronite surface. Magnification × 110. Third Intermediate Period. 336 D. Scott, L. Dodd / Journal of Cultural Heritage 3 (2002) 333–345 the corrosion crust with longitudinal cracking, a feature dates to the Third Intermediate Period or slightly later in the which is not uncommon in bronzes which have suffered Late Period. It is possible to attribute the latter date for this from very severe corrosion during burial, commonly asso- figurine, based on the technical examination of the evi- ciated with chlorides in the soil. Overlying this crust, and dence, including the propensity for Third Intermediate intercalated with it, is the chalky-light blue corrosion crust Period and Late Period (especially 25th and 26th Dynasty) that locally varies in colour from very pale to deep blue, also archaism, incorporating the use of models from the New incorporating quartz grains and other soil minerals.

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