Enamel paint techniques in archaeology and their identification using XRF and micro-XRF M. Hložek a , T. Trojek b,n , B. Komoróczy c , R. Prokeš b a Methodical Centre of Conservation-Technical Museum in Brno, Purkyňova 105, 612 00 Brno, Czech Republic b Czech Technical University in Prague, Department of Dosimetry and Application of Ionizing Radiation, Prague, Břehová 7, 115 19 Czech Republic c Institute of Archeology of the Academy of Science of the Czech Republic, Brno, Czech Republic HIGHLIGHTS  Glazed artefacts from the fortified Roman camp Burgstall were analyzed with XRF.  Colorizing of blue enamels with cobalt oxides was excluded.  Advantageousness of both macro- and micro-XRF scanning of artefacts was demonstrated.  Confocal XRF revealed a rare technique of painted enamel. article info Article history: Received 6 November 2015 Received in revised form 31 January 2016 Accepted 7 February 2016 Available online 8 February 2016 Keywords: X-ray fluorescence Scanning Enamel Microanalysis abstract This investigation focuses in detail on the analysis of discoveries in South Moravia – important sites from the Roman period in Pasohlávky and Mušov. Using X-ray fluorescence analysis and micro-analysis we help identify the techniques of enamel paint and give a thorough chemical analysis in details which would not be possible to determine by means of macroscopic examination. We thus address the influ- ence of elemental composition on the final colour of the enamel paint and describe the less known technique of combining enamel with millefiori. The material analyses of the metal artefacts decorated with enamel paint significantly contribute to our knowledge of the technology being used during the Roman period. & 2016 Elsevier Ltd. All rights reserved. 1. Introduction In connection with new archaeological research and the use of metal detectors, there has been an increased number of dis- coveries of non-ferrous metal artefacts in some cases painted with enamel. The principle of enamel painting is applying a layer of enamel onto a metal surface (typically jewellery made of non- ferrous and precious metals). Even large areas of jewellery and other decorative pieces can thus be covered with impressive glossy colours. In central Europe, metal artefacts decorated with this technique occur. Applying and melting of glass directly on the metal surface enabled covering parts of a jewel with colours. Using enamel for decoration of metals was probably invented shortly after the dis- covery of ceramic body enamel. Molten glass colourized by metal oxides that was pulverised after hardening and applied onto the surface of artefacts is the basis of enamel. The powder was melted in a furnace and sintered with the underlying metal. In compar- ison with ceramic glazes, enamel molten glass was usually colder (1000–1200 °C). In jewellery production, molten glass sintering must respect the melting points of the alloy used; non-ferrous or precious metal. Enamel production has a more than 3000 year long tradition and history. Enamels were used first of all in luxury products. Enamel making was a part of goldsmithery and thus, enamel producers were often goldsmiths who made the whole product. In archaeology, we mostly come across indenting or partition enamel (cloissoné). Colour shades of enamel were reached by the addition of metal oxides to the glass melt. Records indicate that red colour of enamel was achieved by the addition of Cu 2 O and brown hue by Fe 2 O 3  SnO 2 addition produced a white hue and blue colours are usually thought to be the result of ap- plication of cobalt oxides (Filip, 1941). It was in the first four centuries AD (so-called Roman Period) that the Roman Empire reached its largest territorial extent. Its frontiers running along the Danube and Rhine rivers divided the European continent into two culturally and politically different Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/radphyschem Radiation Physics and Chemistry http://dx.doi.org/10.1016/j.radphyschem.2016.02.014 0969-806X/& 2016 Elsevier Ltd. All rights reserved. n Corresponding author. E-mail address: tomas.trojek@fjfi.cvut.cz (T. Trojek). Radiation Physics and Chemistry 137 (2017) 243–247