A Colloidal Description of Tempera and Oil Paints , Based on a Case Study of Arnold

To better understand the painting technique of a given period, information from different sources are usually combined: written statements by the artist or his contemporaries, art technological study of paintings, and chemical analysis. However, does the information obtained from different sources fit together and form an integral picture? Based on a case study of a painting by Arnold Böcklin this question was evaluated. It was found that the correlation between binding media and the properties of paints manufactured from them is not clear and straight-forward as is usually believed. To understand these correlations, colloid chemistry is indispensable. This paper presents concepts of a colloidal description of paints consisting of pigment, egg and drying oil. Various methods for the preparation of such paints and their resulting properties are discussed considering aspects of colloid chemistry and rheology, such as stability of emulsions, gel formation, interactions between pigment particles and binders etc. This paper connects a broad variety of information, aspects, models and hypotheses that cannot be discussed in complete detail here. It is intended as a starting point for future discussions and research into various aspects of paints and painting.