Method for Radiographing the Topography of Oil Paintings

Abstract

Polyethylene glycols (PEG) can be detected in wood by their in situ formation of coloured complex compounds. Solutions of potassium bismuth iodide/barium chloride and of bromine/potassium iodide are suitable for sprayingdirectly onto wood, and may even be used on dark-coloured wood by mixing chalk powder into the reagent. By adopting a print-off technique onto damp filter paper, the distribution of PEG in wood can be demonstrated even more exactly, even from very small samples. Print-offs are developed into differentiated coloured pictures withsolutions of potassium bismuth iodide/barium chloride, iodine/potassium iodide or ammonium cobalt (II) thiocyanate.