Pablo Picasso is widely regarded as one of the most influential artists of the twentieth century, having pioneered a variety of new styles in painting, sculpture, and other artistic forms. Besides introducing avant-garde art styles, he also innovated in the use of non-traditional materials. For example, a widely-held view has been that Picasso employed the ordinary house paint Ripolin in place of conventional artists’ paints in some of his artwork. Over the years art historians have used different approaches in an attempt to determine which of Picasso’s paintings incorporate Ripolin. This task is not as straightforward as one might suppose, because many of the ingredients in Ripolin were also present in the artists’ paints used by Picasso. A recent collaborative effort between Art Institute of Chicago A.W. Mellon Conservation Scientist Francesca Casadio, and Advanced Photon Source (APS) and Argonne National Laboratory physicist Volker Rose has demonstrated conclusively that pigment from one of Picasso’s paintings is, indeed, derived from the Ripolin-brand house paint of that era.
Paints normally contain a binder, made of synthetic or natural polymers, that imparts a characteristic liquid or pasty consistency so they can easily cover and adhere to a surface. Other paint ingredients include pigments (for color), and additives and fillers that may impart specific characteristics like abrasion resistance or reduced drying time. The binder, pigments, and additives are dispersed throughout a solvent, such as water or mineral spirits, which evaporates as the paint dries.
A specific type and brand of paint can be determined by the proportion and distribution of elements within its ingredients. Many techniques are available for identifying the composition of paintings: multi-spectral imaging (utilizing multiple frequencies of light); portable x-ray fluorescence imaging; x-ray diffraction performed at synchrotron facilities; and several others. None of these techniques, however, has proven capable of discerning the composition and distribution of elements within the pigment particles found in many paints. Zinc oxide pigments, for instance, range in size from 200 to 1,000 nm (0.2 to 1 µm). Conventional imaging techniques are often incapable of determining whether a particular element resides in the fillers, additives, or pigments of a particular paint.
Read more at: Phys.org