Investigation of paper collages by near infrared imaging techniques

The purpose of a study is to demonstrate the application of near-infrared (NIR) chemical imaging measurements to the characterisation and authentication of paper collages. Paper collages or photomontages from the Dada art movement and from other artists of the 1920s and 1930s are very popular among today’s art collectors, and there exists an active art trade in these works generating high sales values. Paper collages are the subject of forgeries and fraud. In most cases, the forgeries cannot be detected on the basis of scientific art expertise only. Chemical analysis methods must also be employed. PTS has a special expertise in paper analysis and in several cases has already assisted criminologists in revealing forgeries of paper art works. The analytical methods that are predominantly used are IR, NIR and Raman spectroscopy and corresponding spectral imaging techniques.