Low energy, long wavelength x-rays produced by an x-ray tube set below 15 kilovolts. Soft x-ray analysis is also called low energy radiography or grenz radiography. The low energy x-rays border on the upper end of ultraviolet energy. The images are exposed on photographic film positioned closely (10-15 inches) to the x-ray tube since the soft x-rays are partially absorbed by air (Kushel). The exposed object does not have to be in intimate contact with the film. The image is produced by the transmission of x-rays through the object. Watermarks, or less dense regions, will transmits higher amounts of x-rays. Metallic inks or heavy metal pigments will absorb the radiation. Carbon based inks will usually not be recorded. Soft x-radiography is used for imaging paper structure, watermarks, inks, parchment, textiles, leather and basketry.
Synonyms and Related Terms
low energy radiography; soft x-rays; grenz radiography; radiographie X à basse tension (Fr.); Niederspannungsradiographie (Deut.); radiografia de raios X de baixa tensõa (Port.)
- Kushel, D.: Radiographic Methods Used in the Recording of Structure and Watermarks in Historic Papers, in: F. W. Robinson, Fresh Woods and Pastures New. Seventeenth-Century Dutch Landscape Drawings from the Peck Collection, Chapel Hill 1999, S. 117–140
- H.Tomimasu, D.Kim, P.Luner, M.Suk, "Comparison of Four Paper Imaging techniques: Beta Radiography, Electrography, Light Transmission and Soft X-radiography" TAPPI Journal, 74(7):165-175, 1991
- H. Van Hugten, Weichstrahlradiographie zum Beispiel bei Papier, Proc. Symposium Zerstörungsfreie Prüfung von Kunstwerken Berlin (19-20/11/1987) DGZfP Berlin