Preliminary investigations of the binding media of paintings by differential thermal analysis

Differential thermal analysis has been used to study the binding media of paintings. To assist in the interpretation of the DTA curves known organic materials which are commonly used in paintings such as linseed oil, egg yolk and their mixtures with pigment (e.g. linseed oil/egg yolk/ ZnO) were initially investigated together with paint films containing linseed oil/lead white and some additions of proteinaceous material. The paint films had been prepared in the period 1915–1941. It appears as though DTA or DSC can be used both to characterize the binding media (i.e. to decide whether oil or protein appears as the main component), and to provide an indication of the age of the painting.

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Zusammenfassung Mit Hilfe der DTA werden die Bindemittel der Farbschicht von Gemälden untersucht. Um die Deutung der DTA-Kurven zu erleichtern, wurden zunächst bekannte, häufig in der Malerei benutzte organische Stoffe wie Leinöl, Eidotter und ihre Mischungen mit Pigmenten (Leinöl/Eidotter/ ZnO) sowie in den Jahren 1915–1941 hergestellte Anstrichfilme untersucht, die Leinöl/Bleiweiss mit einigen Zusätzen eiweisshaltiger Stoffe enthalten. Es scheint, dass die DTA oder DSC sowohl zur Charakterisierung der Bindemittel brauchbar ist (das heisst zum Nachweis ob öl oder Protein die Hauptkomponente darstellt) als auch Hinweise zum Alter der Gemälde liefert.

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Thanks are directed to the German Academic Exchange Service (DAAD), the South Australian Institute of Technology Internal Research Grant Scheme, and F.S.E. Scientific for their support; and to the Doerner Institute in Munich for the full use of laboratory facilities for a period of up to 12 months, and also for the pigment determination which was carried out by Frau Junghans.