Contents lists available at ScienceDirect Journal of Archaeological Science: Reports journal homepage: www.elsevier.com/locate/jasrep Reflectance transformation imaging. First applications in cultural heritage in Argentina M.M. Morita a, ⁎ , F.D. Novoa a , G.M. Bilmes a,b a Laboratorio de Ablación Láser, Fotofísica e Imágenes 3D, Centro de Investigaciones Ópticas (CONICET-CIC-UNLP), Cno. Parque Centenario e/ 505 y 508 Gonnet. C.C. 3 (1897) Gonnet, Buenos Aires, Argentina b Departamento de Ciencias Básicas, Facultad de Ingeniería, Universidad Nacional de La Plata, Argentina ARTICLE INFO Keywords: Reflectance transformation imaging Archaeological bones Laguna de los Pampas Recoleta Cemetery Inscriptions ABSTRACT In this article we present two cases of Reflectance Transformation Imaging (RTI) applications. This computa- tional photographic method, based on the acquisition and processing of images, helps to reveal details of the surface of an object that are not visible by direct observation or by standard photography. In the first case, RTI was applied to faunal bone remains that were found during archaeological rescue tasks in Laguna de los Pampas, Province of Buenos Aires. The RTI analysis of these remains with traces of manufacturing and/or use has in- creased the knowledge of bone technology for this area. In the other case, RTI was applied to a funerary column of the Recoleta Cemetery, located in the city of Buenos Aires, in order to recover the low relief recorded on it. In this way it was possible to rescue the historical and heritage value of the vault. 1. Introduction Reflectance Transformation Imaging (RTI) technique is a computa- tional photographic method based on the acquisition and processing of images of a fixed object. The result is an interactive digital image of the object, which can be illuminated virtually from any direction. This technique allows to reveal details of the surface of the object that are not visible by direct observation or by standard photography, such as marks, cracks, modifications in the relief, holes, etc. (Malzbender et al., 2001; Palma et al., 2010). It is an alternative tool for the study and conservation of cultural heritage (Mudge et al., 2005; Yilmaz et al., 2007, 2008; Díaz-Guardamino and Wheatley, 2013; Cosentino et al., 2015; Pagi et al., 2017; Morita and Bilmes, 2018). This paper presents two cases of RTI applications. In the first one it was applied to faunal bone remains that were found during archae- ological rescue tasks in Laguna de los Pampas, located in the southeast of the Lincoln city, Province of Buenos Aires, Argentina. Groups of hunter- gatherers had settled there at different times during the Holocene. These societies recurrently exploited the guanaco for their subsistence (Politis et al., 2012). In addition, they used their bones to make in- struments (tips, bevels, blunt tips, etc.) (Álvarez, 2014). The pieces recorded with RTI correspond to elements that are debris from the manufacture of bone instruments and are housed in the INCUAPA in- stitute (Archaeological and Paleontological Investigations of the Pam- pean Quaternary) of the National University of the Center of the Province of Buenos Aires (UNICEN). All the bone pieces belong to the guanaco species. These remains had one or more of the following characteristics: scraping, grooving and perimeter sawing (Álvarez, 2014). These modifications are produced during the manufacture of the artifacts in bone and the study of them in the waste allows inferring what techniques were used by the hunter-gatherers for that purpose. The bones show marks of scraping and polishing that could have been done during cleaning and preparation. Also, there are tracings of longitudinal grooves (grooving) in the diaphysis, made with the pur- pose of separate parts of the element. With the same sense, perimeter marking or sawing could have been made in the epiphyses, which usually constitute the waste of this sequence of steps (Campana, 1980; Choyke, 1997; Álvarez, 2014). The analysis with RTI of these remains with traces of manufacturing and/or use allows increasing the knowl- edge of bone technology for this area. In the second case, marks on a funeral marble column placed in the Recoleta Cemetery (City of Buenos Aires) were analyzed with RTI. Part of its inscriptions is hidden because of the deterioration caused by the erosion produced by rain and wind. Dirt is observed in the interstices of the stone grains. Also, it presents biological deterioration such as bio- film, and deteriorations inherent to marble, such as external calcifica- tions and distinguished erosion. On the right side there is a veining with a greater degree of erosion than the rest, in which the relief of the letters is completely lost. RTI was applied to recover the low relief re- corded on it. In this way it was possible to rescue the historical and https://doi.org/10.1016/j.jasrep.2019.101899 Received 19 February 2019; Received in revised form 23 May 2019; Accepted 14 June 2019 ⁎ Corresponding author. E-mail addresses: mercedesm@ciop.unlp.edu.ar (M.M. Morita), novoafd@gmail.com (F.D. Novoa), gabrielb@ciop.unlp.edu.ar (G.M. Bilmes). Journal of Archaeological Science: Reports 26 (2019) 101899 2352-409X/ © 2019 Elsevier Ltd. All rights reserved. T