cftore.blogg.se

Finally, the top layer is the surface of dust, dirt, grime, smoke and grease that has built up on the varnish layer. This may consist of several coats including underpainting, overpainting and glazes. Next is sizing or ground which prepares the first layer to receive the paint. This is usually canvas, paper, wood, parchment or metal.

The surface of virtually all paintings is typically made up of at least five layers (see Fig. Understanding the surface of a painting will help you conduct a more accurate black light examination. The larger the size and the more powerful the black light, the less the effect room lighting has on the examination. It's generally best to conduct your examination under reduced or dim room lighting. You are looking for a difference, not a specific color. In one case the original surface might go black and the repair materials might fluoresce. Either new material has been added or parts of the original material have been removed. The different appearance is your clue that the original surface has been disturbed. You are looking for areas that look different than the surrounding surface. Whether you see colored fluorescence or solid black is unimportant. Another material may absorb and retain the energy and appear black. Sometimes the energy is absorbed and released in colored visible light called fluorescence. Different materials react in their own way when struck by this energy. Black light may be thought of as a stream of invisible energy. Ultraviolet radiation, commonly called black light, is a low cost scientific way to view repairs and damages that may be invisible in ordinary light.Īlthough a detailed understanding of how black light works is not necessary to use it, a basic grasp of the principles is helpful.

Magnification and strong artificial light can help catch mechanical damages such as punctures and tears but are of limited use in detecting conditions beneath the visible surface.

Technical advances in repair materials and techniques can now make most alterations and restorations invisible to the human eye. Black Light Examination of Paintings and Prints