Cornwall, light and landscape

I have sometimes heard people say, “Oh, you paint in Cornwall. They do say there’s a wonderful clarity of light down there.”

I have often been puzzled by what they mean by ‘clarity of the light’. 

The most obvious fact is that the air down here is usually  ‘fresh’; that’s to say it’s relatively unpolluted by smoke or exhaust fumes. Going back, over 50 years ago, there was a lot more smoke in general. Coal was used everywhere – in domestic fireplaces, steam trains, factory boilers and power stations. Road vehicles often ran with smoky engines and the air in cities was polluted and unpleasant.

By the standard of those days I suppose you could say the Cornish atmosphere was generally clean, and the light pretty clear. The prevailing south-west wind blows off the sea and most of Cornwall is only a few miles from the coast. 

But then as a landscape painter I also look at the way the atmosphere affects the light in other ways. One of the most characteristic things about Cornwall is the amount of moisture in the air. Water scatters the light and makes things more hazy.

I have painted in Zambia, in Australia, and in the foothills of the Andes in southern Peru on the edge of the Atacama desert. In those cases the air was dry, and you could see huge distances with far greater clarity than ever you could in Cornwall. There was little haze.

Here, in Cornwall, the water in the air reduces the distance we can see. On a hot summer’s day a blue haze fills the distant view as the light scatters – the higher frequency of the blue end of the light spectrum makes it more fidgety and it bounces off the water vapour in the air more than light at the red end. That’s why the distance fades into blue or purple, and indeed why the sky looks blue on a cloudless day. The red and yellow light from the sun comes through the atmosphere into our eyes less scattered, whereas the blue bounces more out wide into the rest of the sky.  Atmospheric moisture actually makes the air ‘thicker’ and more difficult for light to get through unimpeded.

On other days water is still a dominant feature. When it becomes overcast a grey mistiness gradually impedes the longer view, and when it’s raining then dark veils draw across the horizon, even supposing low cloud hasn’t already obscured nearly everything already. Here, it’s a very unusual day when I can see clearly for 20 miles or more, whereas under the cloudless skies of Arequipa in southern Peru there was hardly a day when I couldn’t. 

Comparing dry Arequipa to our moist Cornish climate I observe that shadow areas on a sunny day are very different. 

In the hard cloudless sunlight of Arequipa the sunlit side of the street is very bright, and by contrast the shadow side is very dark. 

In a Cornish street on a sunny day the sunlit side is bright but on the other side the shadows are softer and reveal much more detail. The forms of things are clearer because they are more illuminated. There is a generalised ‘glare’ from the scattering of the light by the moisture-laden air which backfills the shadowed areas, and because the blue end of the spectrum is scattered more, then this backfill tends to illuminate the shadows with blue light. By contrast, in Arequipa, where there’s no moisture and the light is much less scattered, the shadow side tends to disappear into blackness.

So in that sense, in the shadow zones, in a Cornish landscape on a sunny day there would be a lot more to see. The haziness which makes distant views fade away to blueish-purple in the thick air, also makes the ‘scatter-glare’ all around us which then illuminates the shadows in the close views. 

So an atmosphere of scattered light makes the picture much softer and less deeply contrasted. It feels brighter overall, bringing the forms in the shadowed areas much more into play in any pictorial composition. There’s no part of the pictorial space which is unlit (black). 

An equivalent landscape around Arequipa would be lit hard in sunny areas and be very dark, even black, in the shadow areas. Forms in the shadows might not be distinguishable.

All that I have said above holds true if you, yourself, are looking at the brightly lit areas – which we naturally tend to do. But as we do that, then the pupils of our eyes become smaller to admit less light, so our eyes can cope with the brightness and our vision doesn’t become ‘glared out’. But by letting in less light our eyes lose the ability to see what’s in the dark shadows. Only when we turn away from the light and step into the shadows do our eyes readjust, our pupils dilate to let in more light, and then things in the shadows start to become distinguishable. 

The difference is that whereas in Arequipa the shadows are deep, the shadows in Cornwall get backfilled with the blue glare of scattered light and this illuminates the scene, even when not in direct sunlight. It lifts the shadows. 

That could be said to give a sort of clarity.