How Colours Are Discovered

By Liz Stinson on 07 Apr 2018 at 8:00AM

In the early 18th century, German chemist Johann Jacob Diesbach was at work in a laboratory trying to make a red pigment out of cochineal insects, the tiny bugs whose extract dyes everything from food to lipstick. Diesbach hypothesised that he could combine the carmine extract with alum, iron sulphate, and potash to make the pale red hue he desired. There was a problem, though. The potash Diesbach used had been contaminated, which altered the chemical makeup of his pigment. Instead of red, Diesbach had unwittingly created something far more valuable: a deep ocean-like blue.



Prussian Blue

For centuries, blue was considered one of the rarest of pigments, found only in small quantities in nature. Pigments like lapus lazuli, made from a metamorphic rock of the same name, was said to have a value akin to precious metals like gold. But thanks to Diesbach’s chemical mishap, the pigment could now be made synthetically; faster, cheaper, and in greater quantities than ever before. Diesbach’s blue, called Prussian Blue, is considered one of the first synthetic colours to ever have been made. Since then, we’ve found many more.



YInMN blue

It’s strange to think of colour as something that can be discovered. Ask most scientists and they’ll tell you that’s not really how it works, anyway. “You can’t discover a colour,” said Mas Subramanian, a chemist at Oregon State University who in 2009 created a blue pigment called YInMN blue. “You can only discover a material that uses a particular reflection of a particular wavelength.” Semantics aside, humans have created new pigments—whether through intentional scientific inquiry or pure happenstance—for as long as we’ve been around.



Tyrian purple

Our Stone Age ancestors learned they could grind up clay to create ochre, a rich, earthy red. The ancient Egyptians mined copper carbonate hydroxide minerals in the Sinai Peninsula to produce a rare green hue. Later, during the industrial revolution, scientists used advanced chemistry to create colours though deliberate—or in the case of Prussian Blue and Tyrian purple—accidental scientific explorations. This boom in bold synthetic colours helped spawn the Impressionist art movement, since painters could more accurately recreate the colours they saw in nature. “The number of synthetic pigments have increased dramatically since then,” said Narayan Khandekar, director of Harvard’s Straus Centre for Conservation and Technical Studies, where more than 2,500 pigments are stored. (In a new book, An Atlas of Rare and Familiar Colour, Khandekar and his colleagues unpack the history of the collection’s pigments.)


http://www.gizmodo.co.uk/2018/04/how-colours-are-discovered/