Editor's note: This is a revised and updated version of a column that was first published in The Citizen in 2013.
I enjoy painting. It started when I was a kid and finger painting for the first time. I mean where else can you stick your hands in ooey, gooey stuff and not get in trouble?
Finger painting is also a chance to learn about mixing colours. Red and yellow give you orange. Blue and yellow give green. Blue and red give purple. And by changing the amount of red, blue, or yellow, all sorts of shades are available. The whole rainbow is there for the asking. Of course, there is a lot more to painting than simply swirling colours on a piece of paper.
There is a lot of science involved.
Paints are a mixture of pigments or dyes and a medium of some sort. Getting the mixture for the medium right and finding lightfast colours challenged scientists in the past. Or maybe I should say "challenged artists in the past" since they were often one and the same.
Consider oil paints. The precursors to modern oil paint date back to the earliest Mediterranean civilization. Hot beeswax and mineral pigments such as the oxides of iron, copper, and manganese, called encaustics, were used to paint murals. Tempura was developed around the same time employing pigments mixed in a medium of eggs, water, and vegetable oil.
Egg, as anyone who has ever left the breakfast dishes for too long knows, dries very fast to give an incredibly hard film. This made eggs an excellent medium for paints requiring a short drying time. But it wasn't the best medium for overall durability nor for keeping the colours true.
Olive and other vegetable oils soon became the principle medium giving rise to oil paints. These oils are pliable and fluid, able to hold pigments and provided a lightfast medium. Unfortunately, most oils take a very, very long time to dry.
Artists experimented with other media formulations mixing all sorts of compounds in with their oil paints. Many of the formulations were kept secret so the artist would have a monopoly on a particular colour or formulation. These oil paint formulas were handed down from master to apprentice. It was generally the apprentices who spent their days grinding pigments and mixing media to make the paints the master required.
Oil painting, in the modern sense, emerged during the 15th century when the Flemish painter Jan van Eyck developed a stable medium based on linseed oil. His painting Giovanni Arnolfini and his Wife, which hangs in the National Gallery in London, is considered one of the first to use the linseed oil based paints that are still used today.
Van Eyck's experiments lead to a craft of paint-making separate and distinct from the artist's studio. Modern artists buy paints premixed in tubes from the factory. While most of these paints are based on a linseed oil medium with similar chemical compounds present, the quality of oil paints varies significantly between suppliers. Most artists find a brand they like and stick to it.
Part of the reason for this is the drying of oil paint is a very slow process. Light from the sun or artificial sources, oxygen from the air, and water vapour react with the linseed oil to form a polymeric elastic solid. Oil paints don't dry so much as they undergo a polymerization reaction to form a compound called linoxin. In essence, dried oil paint is a plastic polymer generated by chemical reactions over time with pigments or dyes suspended in it.
The rate of drying - or the rate at which the polymerization occurs - can often be critical to the overall product. Different oil paint formulations employ different drying agents to speed up or slow down the rate of these chemical reactions. Compounds such as aluminum hydrate, aluminum stearate and cobalt salts can alter the drying process. Individual artists search for paints which matches the way they work and tend to stick to one so all of the oil paints cure at the same rate.
With oil paints, there is also the issue of opacity versus transparency, which depends upon the pigment and other compounds in the paint and the issue of colourfastness with respect to photochemical decomposition and the issue of blendability and... well, oil paints are a complicated business.
Many of the paints used in the past were happy accidents or byproducts of other chemical processes. Over the past half-century with the development of an understanding of colour, much colour research has seen scientists and artists working side-by-side.
Of course, the real measure of an oil painting is not so much the science. After all, that is not what we admire as we gaze upon the Mona Lisa with her enigmatic smile.
It is the art we see.
But without the science, the art would not happen.
