ABSTRACT
ABSTRACT: Some binders used in oil painting are supposed to have special properties and advantages because of their “thixotropic” behaviour: they would flow easily in contact with the brush, but they would be like a gel at rest. Time factor is not clearly established and results in confusion between shear thinning and thixotropy when describing them. In this work we have analysed rheological properties of 8 different binders: 2 historical artisan recipes and eight nowadays commercial media. The results revealed that handmade Rubens according Mytens turned to be a Newtonian fluid (viscosity is independent of shear rate), while the rest of binders were highly shear thinning. These seven non-Newtonian systems had also a viscosity decreasing with shear time, but only the handmade Van Eyck according Mayer recovered part of its initial viscosity after resting. Therefore, most of binders analysed do follow the behaviour that is described in painting manuals and handbooks.
