Adam Aurèle J L, Planken Paul C M, Meloni Sabrina, Dik Joris
Faculty of Applied Physics, Department of Imaging Science and Technology, Delft University of Technology Lorentzweg 1, 2628 CJ Delft, The Netherlands.
Opt Express. 2009 Mar 2;17(5):3407-16. doi: 10.1364/oe.17.003407.
We show terahertz reflection images of hidden paint layers in a painting on canvas and compare the results with X-ray Radiography and In-frared Reflectography. Our terahertz measurements show strong reflections from both the canvas/paint interface and from the raw umber/lead white interface, indicating sufficient refractive-index contrast. Our results show that X-rays cannot be used to image through the lead white pigment which effectively blocks the X-rays. Although Infrared Reflectography is capable of vaguely observing the hidden paint strokes from the canvas side, we show that only terahertz imaging is capable of providing information on the thickness of the hidden paint layers. Terahertz imaging is thus shown to be a powerful imaging method for art historians, conservators and conservation scientists.
我们展示了一幅帆布油画中隐藏颜料层的太赫兹反射图像，并将结果与X射线照相术和红外反射照相术进行了比较。我们的太赫兹测量结果显示，在画布/颜料界面以及生赭石/铅白界面均有强烈反射，这表明存在足够的折射率对比度。我们的结果表明，X射线无法穿透有效地阻挡X射线的铅白颜料进行成像。虽然红外反射照相术能够从画布一侧模糊地观察到隐藏的笔触，但我们表明只有太赫兹成像能够提供隐藏颜料层厚度的信息。因此，太赫兹成像被证明是艺术史学家、文物修复师和文物保护科学家的一种强大成像方法。
