Source: Asahi.com.

    New technology developed by a government research institute and a state-run university allows scientists to sniff out art forgeries by pinpointing exactly when the piece was painted.

    Scientists use a special electromagnetic wave, a terahertz wave, to scan the paintings. The rate of absorption of the wave helps to identify the ingredients of the paint, which researchers can then use to date the picture precisely.

    The technique has been developed by the National Institute of Information and Communications Technology (NICT), based in Koganei, western Tokyo, and Tohoku University in Sendai.

    They will soon announce the development in an online version of a magazine published by the Institute of Electronics, Information and Communication Engineers (IEICE).

    NICT researcher Kaori Fukunaga and others got more than 100 paint samples of various eras from workers who were restoring artwork in Italy. The researchers applied terahertz waves to them and compiled a database of each paint and its absorption rate.

    The database showed that even if the paints appear identically white to human eyes, their differing absorption rates reveal that they are different substances.

    Once scientists have identified the ingredients, they can date the painting.

    For instance, white lead was used in paint until the 19th century, when zinc oxide became common. Since the 1920s, the use of titanium white has spread.

    Terahertz waves can distinguish paints made not only from minerals but also plants, and even binders, such as oil and acryl, which make the paints adhesive.

    The wave does not emit radioactivity, so it does not harm users.

    Terahertz waves are also useful in detecting explosives and illegal drugs.

    ¡°Terahertz waves can be also used to detect food additives and pollutants of the natural environment,¡± Fukunaga said. ¡°I want to make the (scanning) device smaller so that it can be used in various industries.¡±