The emergence of a new paint media in the first half of this century has lead to a number of historically important paintings undergoing degradation not previously encountered. Through understanding the method of production and synthesis, and analysis of commercial and model materials the structure of oil modified alkyd resins has been postulated. Through exposure to high intensity light artificial aging has been achieved and changes in structure have been deduced. This has lead to a bet- ter understanding of the curing process and how this relates to the degradation of the polymeric material. A method of identification of the polyol used has also be established.
