then the object is not

nation of a piece fails to reveal whether it is authentic or forged, investigators may attempt to authenticate the object using some, or all, of the forensic methods below:
Portrait of a Woman, attributed to Goya (1746-1828). X-ray images taken of this painting in 1954, revealed a portrait of another woman, circa 1790, beneath the surface. X-ray diffraction analysis revealed the presence of zinc white paint, invented after Goya's death. Further analysis revealed that the surface paint was modern and had been applied so as not to obscure the craquelure of the original. After analysis, the conservators left the work as you see it above, with portions of old and new visible, to illustrate the intricacies of art forgery, and the inherent difficulty of detecting it.Carbon dating is used to measure the age of an object up to 10,000 years old. “White Lead” Dating is used to pinpoint the age of an object up to 1,600 years old. [6] Conventional X-ray can be used to detect earlier work present under the surface of a painting (see image, right). Sometimes artists will legitimately re-use their own canvasses, but if the painting on top is supposed to be from the 17th century, but the one underneath shows people in 19th century dress, the scientist will assume the top painting is not authentic. Also x-rays can be used to view inside an object to determine if the object has been altered or repaired. X-ray diffraction (the object bends X-rays) is used to analyze the components that make up the paint an artist used, and to detect pentimenti (see image, right). X-ray fluorescence (bathing the object with radiation causes it to emit X-rays) can reveal if the metals in a metal sculpture or if the composition of pigments is too pure, or newer than their supposed age. Or reveal the artist’s (or forger’s) fingerprints. Ultraviolet fluorescence and infrared analysis are used to detect repairs or earlier painting present on canvasses. Atomic Absorption Spectrophotometry (AAS) and Inductively Coupled Plasma Mass Spectrometry(ICP-MS) are used to detect anomalies in paintings and materials. If an element is present that the investigators know was not used historically in objects of this type, then the object is not authentic. Dendrochronology is used to date a wooden object by counting the number of tree rings present in the object. This is of limited use, though, as to date the piece accurately the wood needs to have about 100 rings. Stable isotope analysis can be used to determine where the marble used in a sculpture was quarried. Thermoluminescence (TL) is used to date pottery. TL is the light produced by heat, older pottery produces more TL when heated than a newer piece. [7] A feature of genuine paintings sometimes used to detect forgery is craquelure.