Publication Type:Journal Article
Source:Studies in conservation, Volume 14, Number 3, p.96-118 (1969)
Keywords:infrared reflectography, Medieval, optical properties, paint layers, paintings, underdrawings
Infrared reflectography, a method of improving the detectability of underdrawings in Medieval paintings, is discussed. It is shown that the results can be explained with the Kubelka-Munk analysis of the optical properties of paint films. Measurements are described providing a plot of the paint layer thickness required to hide an underdrawing, against the wavelength. Such curves show a maximum around ? = 2.0 microns. Infrared to visible image translation systems are surveyed to illustrate the choice of an infrared vidicon television system to obtain reflectograms. This system is responsive to radiation up to 1.9 microns. The interpretation of infrared reflectograms is briefly discussed. Limitations of the method are indicated.