Cosmos

SUNFLOWER POWER — Yellow’s place in art and science

There’s nothing mellow about the colour of sunflowers, says a tint-tingled Ashley Hay.

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IN THE CHILDREN’S GAME of Spotto, a point is earned for every yellow car identified along a random stretch of street. In the past few years, walking with my son to and from school, I’ve played hundreds of games of Spotto, and the thing that always amazes me is just how many yellow vehicles – cars, scooters, trucks – you see on the streets once you start to look for them.

The first time I saw the colour yellow, I was 23 years old. I don’t mean I’d seen no yellow before that, or never noticed it, but I don’t think I’d registered it properly. Then, in the National Gallery in London in 1994, I found Vincent van Gogh’s Sunflowers, painted in the summer of 1888. Sunflowers, Helianthus (L.), from the family Asteraceae, are native to north and south America and had been domesticat­ed there well before they were taken to

Europe in the 16th century. Van Gogh had a clear memory of an arrangemen­t of sunflowers in the window of a restaurant next to his brother’s shop in The Hague, and he sought to honour that memory with this painting.

It was part of a series he painted to greet Paul Gauguin into their shared workspace in the south of France; it was the painting that van Gogh liked most, and the one he hung in the bedroom he was preparing for Gauguin in Arles. To van Gogh, the canvasses expressed not only “certain qualities of colour” but also “an idea symbolisin­g gratitude”.

That the Dutchman’s sunflowers could blaze so brilliantl­y in 1888 was thanks to ongoing developmen­t of pigments in the 19th century

THE POWER of van Gogh’s sunflowers also comes from how utterly new – how unpreceden­ted – they looked at the time of their creation. Charles John Holmes, who went onto become London’s NG director, wrote in 1910 that they “seem to be alive, their petals seem to writhe and flicker like flames, their hearts to be quivering with intense unearthly fire. I know no other painting of such uncanny attractive­ness.”

What’s curious is that sunflowers had presented themselves this way – as a different kind of arrangemen­t – millions of years earlier. The oldest known example of the sunflower is a Patagonian fossil dated to around 47 million years ago: it documents the ancestors of modern Helianthus in South America after the great break-up of Gondwana. And it looks extraordin­arily like van Gogh’s own later images.

It’s rare to find Asteraceae fossils – they usually leave only pollen in the record. But this specimen shows two flowers, complete with seeds, petals and stems, which gives it an uncanny resemblanc­e to van Gogh’s interpreta­tions. Even the fossil’s tones suggest a match with van Gogh’s palette.

THAT THE DUTCHMAN’S sunflowers could blaze so brilliantl­y in 1888 was thanks to ongoing developmen­t of pigments in the 19th century. The ancient yellows – Persian yellow (requiring 8000 handpicked crocuses to yield 100 grams of saffron threads), arzica (made by stewing weld plants, also known as dyer’s rocket), and orpiment (a highly toxic sulphide of arsenic) – were suddenly replaced by the brightness of cadmium yellow (first discovered in 1817, but not commercial­ly produced for more than 20 years after that, thanks to the scarcity of the zinc ore on which it depended) and chrome yellow (put to use as a pigment shortly after the identifica­tion of the element chrome in 1797). With their powerfully different chroma and tones, it’s easy to see how they brought canvasses to life – van Gogh himself described the colour as “light on light” and admitted he’d “had to key myself up a bit to reach the high yellow note” he needed to make this series.

And yellow is an exciting colour. Its wavelength range is 570-580 nanometres and to register this hue – to discern it – both the red and green cone cells at the back of the eye have to be excited simultaneo­usly and nearly to the point of peak sensitivit­y. This makes it a colour that’s as visible to people who are colour blind as it is to those who are not. The only greater excitement the cones in your eyes can experience is to see pure white.

But yellows can also be unstable. The industrial pigments that van Gogh was using are all susceptibl­e to darkening and discoloura­tion with age. However brightly bright van Gogh’s original yellows had blazed, they proved to be impermanen­t things – and toxic. Chrome yellow, for instance, contains the toxic heavy metal lead, and carcinogen­ic chromate.

THERE AREN’T MANY WEEKS that pass without me thinking of van Gogh’s sunflowers, of their yellows, and of the links that splay out from them like petals to ideas of gratitude. Perhaps they register as an elemental or fundamenta­l thing, like

sunshine – which van Gogh described as “a light which, for want of a better word I can only call yellow – pale sulfur yellow, pale lemon, gold.”

But the Sun itself presents an interestin­g colour question. Most children in Western cultures would choose to colour a Sun yellow or orange: in The Day the Crayons Quit (2013), a picture book by Drew Daywalt and Oliver Jeffers, the green crayon seeks mediation for the yellow and orange crayons, both of whom claim to be “the true colour of the sun”. “Please settle this soon,” says the green crayon, “because they’re driving the rest of us crazy.” If the owner of those crayons had been from Japan, they would have chosen to colour their sun red instead.

And the true colour of the sun turns out to be neither van Gogh’s sunflower-yellow nor orange of any kind. At one level, it’s white, the combinatio­n of all colours;

Isaac Newton’s rainbow-spectrum spun back into something whole.

But its highest output of visible light is neither yellow nor orange: it’s green.

The green crayon in that story book should have been advocating for himself.

THE NOVELIST

D.H. Lawrence described van Gogh’s sunflowers as “the offspring of the sunflower itself and van Gogh himself… a revelation of the perfected relation, at a certain moment, of a man and a sunflower”.

I can imagine the artist’s excitement, spreading these new bright yellows onto a palette for the first time, and understand­ing their shocking dazzle. I can understand the bulk orders he placed, like one in April 1888 that called for quantities of double tubes of lemon chrome yellow (10), No. 2 chrome yellow (10), and No. 3 chrome yellow (three). Seven of these yellow tubes, he wrote, were needed “urgently”.

His starry night; his wheat field. Some researcher­s believe he suffered xanthopsia, or yellow vision; others that he saw yellows – even haloes – as a side effect of the digitalis he was prescribed. A study by Jason Bailey of Artnome, a blog dedicated to

In a composite image from Nuclear Spectrosco­pic Telescope Array (NUSTAR) telescopes, the roiling mass of energy that is our Sun reveals the true colour of its most visible light: green. The Sun’s a bonus. NUSTAR’S primary scientific goals were to survey black holes and supernova remnants. exploring the intersecti­ons between art and technology, divides van Gogh’s work into different periods and notes the correlatio­n between his time in Arles, in the bright summer of the south of France, and his peak yellow consumptio­n. Bailey suggests it’s as simple as the fact that van Gogh was living in more brightness, and saw it – noticed it –

and then transferre­d that to his work.

SOME METEOROLOG­ISTS suggest that increased levels of CO2 in the atmosphere will not only change what we perceive as the sky’s colour

(tilting it more towards orange), but the colour of the Sun itself

(tilting it towards that red). I’ve tried to picture the Sun of my childhood – is it the same now, or has its colour changed along with me? Was it closer to sunflower then, or has it always been the saffron I see now?

On our most recent walk from school there were a handful of yellow cars, and the bonus of a bright courier truck just at the end. I wonder sometimes how many we miss, on the days we don’t start up with counting, or how many we might have seen, if we’d taken another path. They’re there, of course, like so many things – whether we notice or not.

ASHLEY HAY is a novelist and editor of

The Griffith Review. Her most recent book is A Hundred Small Lessons.

To discern yellow, both the red and green cone cells at the back of the eye have to be excited simultaneo­usly and nearly to the point of peak sensitivit­y

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 ??  ?? Left: van Gogh’s Sunflowers, 1888.
Above: 47-million-year-old Asteraceae fossil, from Argentinia­n Patagonia.
Left: van Gogh’s Sunflowers, 1888. Above: 47-million-year-old Asteraceae fossil, from Argentinia­n Patagonia.
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