Micron 65 (2014) 15–19 Contents lists available at ScienceDirect Micron j ourna l ho me page: www.elsevier.com/locate/micron The gigapixel image concept for graphic SEM documentation. Applications in archeological use-wear studies Josep M. Vergès a,b,∗ , Juan I. Morales a,b a IPHES, Institut Català de Paleoecologia Humana i Evolució Social, C/ Marcel·lí Domingo s/n, Campus Sescelades URV (Edifici W3), 43007 Tarragona, Spain b Àrea de Prehistòria, Universitat Rovira i Virgili (URV), Avinguda de Catalunya, 35, 43002 Tarragona, Spain a r t i c l e i n f o Article history: Received 24 February 2014 Received in revised form 11 April 2014 Accepted 11 April 2014 Available online 21 April 2014 Keywords: Use-wear analyses SEM Microscopy Gigapixel image Lithic studies a b s t r a c t In this paper, we propose a specific procedure to create gigapixel-like images from SEM (scanning electron microscope) micrographs. This methodology allows intensive SEM observations to be made for those disciplines that require of large surfaces to be analyzed at different scales once the SEM sessions have been completed (e.g., stone tools use-wear studies). This is also a very useful resource for academic purposes or as a support for collaborative studies, thus reducing the number of live observation sessions and the associated expense. © 2014 Elsevier Ltd. All rights reserved. 1. Issues In certain specialized research fields, it is necessary to associate microscopic observations of different areas of a single sample. Func- tional studies of prehistoric stone tools are such a case. This kind of analysis studies the microscopic deformation and damage to the surface of objects as a result of their use by prehistoric people for daily activities. Complementary to this, microscopic techniques are also employed to observe and analyze the degree to which ancient residue is preserved on tools used for the same activities. Functional analyses therefore need to connect the observed characteristics of several parts, or sectors, of one tool, in order to obtain high quality information about kinematics, the worked material or the relationship between the active edge/s and the haft- ing zones. In these studies it is necessary to alternate between low- and high-magnification observations, in order to document details ranging in size from millimetric to micrometric or nanometric. This procedure is usually performed by direct observation, not- ing the points of interest observed and also capturing micrographs at several magnifications. The working methodology, common to all SEM-based functional studies, implies investing much time in lengthy observations. Nevertheless, even in the case of the most ∗ Corresponding author at: IPHES, Institut Català de Paleoecologia Humana i Evolució Social, C/Marcel·lí Domingo s/n, Campus Sescelades URV (Edifici W3), 43007 Tarragona, Spain. Tel.: +34 604 982 137. E-mail address: jmverges@iphes.com (J.M. Vergès). exhaustive observations, patterns of interest that have not been observed will probably not be detected a posteriori. The graphic documentation obtained only reflects those points – subjectively selected – that have been considered of interest during the obser- vations. This disadvantage becomes more evident during the post- microscopy analysis, in particular when it is carried out by a researcher who has not participated in the data capture, or once it has become hard to remember all the details of the microscopic analysis. When complementary information is required, it is then necessary to return to the SEM or to use other equipment. Opti- cal microscopy is commonly used in functional studies, but like with the electron microscopy, there are some limitations. Optical microscopy can be useful when the area of interest is visible at low magnification. However, the capacity of this equipment may be reduced or limited when high magnification is needed (Borel et al., in press). Additionally, in some cases, the physical properties of the raw material being observed may complicate observation with an optical microscope (i.e. very shiny or translucent materi- als like some flints, obsidian or hyaline quartz). Usually the best option in this case is to study the sample again, this time under the SEM. It is important to note that, when working with archeolog- ical materials, the samples are not always immediately available and, furthermore, their accessibility is often time restricted. Also, in the case of sample availability there are some other restricting factors for the use of the SEM. Exhaustive observations are time con- suming and there may be difficulties in terms of the equipment’s availability, depending upon personal scheduling and also because http://dx.doi.org/10.1016/j.micron.2014.04.009 0968-4328/© 2014 Elsevier Ltd. All rights reserved.