Art
Is that painting valuable? Depends on the chemistry T
BY LARAS SOENARJO
he record for the most expensive painting ever sold is ponents: the pigment and the binder. The pigment is the compound responsible for giving paint held by Leonardo da Vinci’s Salvator Mundi, which was auctioned off for $450 million in 2017. In 2019, the global its colour. It is usually a transition metal complex or a highart market - comprising art galleries, fairs and auctions – saw ly conjugated organic compound. These compounds absorb wavelengths of visible light, resulting in their perceived colour. $64 billion in sales. The binder (e.g. oil, acrylic and gum Arabic in the case of Whilst most painters never sell works in the six to seven figwatercolour paints) is a transparent ure range, these events are becoming compound that adheres the pigment increasingly common. onto a surface of canvas or paper. Generally, a painting is valued acThe range of available pigments cording to its uniqueness. A print is The pigments used on have expanded over the years. 40,000 never as vibrant as an original, and a painting can tell years ago, cavemen only had acnot even the artist can exactly replius much about the cess to five natural pigments; black, cate their previous works. The value brown, red, white and yellow, which is even greater if the painter is critiperiod in which it were obtained from soil, animal fat, cally acclaimed, or deceased. was created, and the chalk, charcoal and minerals. After These days, paintings aren’t bought access the painter the Stone Age, more and more natjust to be admired. The super-rich ural pigments were discovered, such buy art as an investment, perhaps had to certain as ultramarine blue, made from the finding this strategy desirable as unresources. semi-precious gemstone lapis lazuli. like most other investments the value Great advances in the field of is independent of the stock market. chemistry produced synthetic pigA New York City taxi tycoon famously bought a Rauschenberg painting for $900, which near- ments, like Prussian blue (Fe4[Fe(CN)6]3), which was discovered in the early 1700s. Even now, new pigments continue to ly two decades later, he auctioned off for $85,000. With such high valuations for works by brand-name artists, be discovered. YInMn blue, an inorganic compound containing, Yttrium, Indium and Manganese was discovered in 2009. how can we be sure of the authenticity of a painting? The pigments used on a painting can tell us much about the Besides analysing the brushstrokes and artistic style of a painting, which can be subjective, experts analyse the chemi- period in which it was created, and the access the painter had cal make-up of the paint. Paint is composed of two main com- to certain resources.
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