Applications of transmitted infrared radiation to the examination of artifacts

The use of transmitted infrared radiation in the examination of artifacts is shòwn oftento surpass reflected infrared techniques in the ability to image, in paintings and other artifacts, underdrawings, evidence of artists’ changes and working methods, and areas of damage, lossor restoration that are hidden under covering layers. In addition, the technique is shownto have the ability to reveal, often with great clarity, paintings which lie beneath other paintings, even when X-radiography and reflected infrared examination give no indication of the existence of the former. Examples are illustrated, and simple working procedures involving the useof readily available infrared photographic materials or of an infrared vidicon unit are described.