Scientific Methodologies to Identify Art Prints

Modern photoengraving methods can generate forged prints really similar to original ones. Till recently, in order to distinguish between these fakes and original prints, art historian specialized in art prints have been using only magnifiers (magnifying lenses). The aim of the present study was to set up a scientific method based on non-invasive techniques to find out differences between photoengraving reproducing etching of the century XVIII and original etching of the century XVII, and to document them. To this aim, several devices were tested: IR reflectography, Portable X-Ray Fluorescence Analyzers (XRF) and optical microscope. We aimed at analysing mainly the kind ink used and the lines. We chose not to analyse the kind of used paper, since for forged prints antique paper can be used as support. The IR response of the two kinds of print, was found to be not relevant. Ink components, as analysed by XRF were not to be distinguished between the ones used for photoenvravings and for the original prints. With the microscope, small areas showing lines were investigated with a 10X enlargement. Obtained macrophotographies allowed to point out a lot of differences between the two prints. The main ones were: the thickness of the ink, which is greater on originals than on fakes, the kind of light reflection: on originals light is absorbed (ink is dull) while on fakes light is specularly reflected (ink is bright and it seems without consistence), moreover thin and continuous lines in original prints can result broken in forged prints. While the other investigation methods were considered not useful in this study case, microscope gave good results that are easy to achieve and to understand. It represents an easy way of investigation. Microscope can be considered helpful to support art historian during their investigation, and it provides a reliable and affordable way to document the differences between photoengravings and original prints. INTRODUCTION Photoengraving and original prints are going to be more and more similar because methods to create fakes are improving. Art historian using magnifying lenses to distinguish between originals and fakes sometimes find difficulties because of it, anyway this method is implicitly limited because it does not provide any objective documentation. Can science help to achieve objective results and document the traditional subjective judgement given by art historian using magnifyng lenses? Are non-invasive investigations helpful to this aim? In order to broach this topic it is necessary to understand what is a print, how it can be obtained, what is a photoengraving, what may be called original. An original work of art is one that has come from the artist’s own hand. Frequently artists need the expert assistance of the printer because some printing processes are complex, but artist creates the draw and superintends the printing process [3, 4]. Prints are usually on paper and created by the impression of the matrix previously covered with ink. The process is capable of reproducing multiples of the same piece. Each piece is an original because it is not a reproduction of another work of art [10]. A lot of different methodologies exist to create prints. We started studying Zocchi’s engraving because his prints are very popular in Florence and neighbourhood. 1 9th International Conference on NDT of Art, Jerusalem Israel, 25-30 May 2008 For more papers of this publication click: www.ndt.net/search/docs.php3?MainSource=65