SOUTHERN SPAIN IS RIDDLED WITH CAVES: it’s the geology. As glaciers melted and seas receded all that porous limestone literally dissolved, eventually forming valleys, ravines and caves. Some of the earliest humans in Europe built their lives around these caves, made them sanctuaries, took shelter in them. In some areas they still do.

Outside Ronda, near the village of Benaoján is Cueva de la Pileta, a multilevel network of caves. I’d always wanted to go there, and last month the artist David Seaton took me.   

Most of the year Pileta is cool, if not actually cold. But the day we went was hot and bright, the last of Spain’s Indian summer, and even hundreds of meters down it was still strangely warm. Our only light came from LED lanterns we each carried, and single-file, we picked our way down steps cut into the living rock. After squeezing through several narrow channels (full disclosure: I’m a bit claustrophobic) we reached a huge chamber, the height of which we could only guess. I kept wanting to look up at the enormous stalactites and the suede flutter of bats, but I kept my eyes on my feet. The floors were wet and glassy smooth, and I’d already fallen once.

Finally, José, our guide, told us to stop, and we raised our lanterns to find him in front of what looked like an enormous curtain, its folds and channels formed over millennia by flowstone. Motioning for quiet, he said in a low, clear voice “listen”, and then struck one of the channels hard with the heel of his hand.

The sound was incredible. It was like the bong of an enormous underwater clock. It didn’t enter my ear as much as pass through my body. Just as I exhaled, he reached above and struck another channel, sounding a different tone, and then a third, releasing yet another, and so on. The entire chamber and everyone in it seemed to vibrate like a tuning fork, bound within the same frequency. And despite the now stifling heat, I shivered at the thought of hearing actual stone age music.

That sounds farfetched, but that enormous xylophone was just the beginning. When we reached the last chamber, a vast ovoid space directly above another cave, José told us to turn off our lanterns. The darkness was so absolute it was almost solid, and we fell completely silent. Then I felt/heard something like a cross between a hug and a sonic boom as he stomped his foot on the hollow stone floor.

After we’d recovered, we relit our lanterns, laughing and gasping at each other. It was the most noise we’d made, and I realised that in all that time I hadn’t really heard us. Not because we’d been silent, that was impossible, but it was as if our noise was irrelevant because the cave heard no sound but its own.

Okay, that is farfetched. But in my defense, context is everything, and as sensory experiences go Pileta surpassed anything I’ve ever encountered. What’s stranger still is that I mostly remember the cave as something I heard. And after all, I’d gone there to see paintings.

Pileta is one of the most important sites for Palaeolithic art anywhere in the world. Since 1905, when a local farmer rediscovered the cave, scholars and archaeologists have found nearly 900 paintings or, more accurately, drawings –they were made using bits of charcoal, or applied by hand in a mixture of earth pigments and animal fat. The earliest examples are possibly 30,000 years old. 

And they were stunning. As we made our way through the caves, we’d stopped to look as José, combining deep knowledge with a real flair for showmanship, pointed out drawings with a flashlight. The range was astonishing. Not only animals (too many to list), but also stickmen, and infinite charcoal ‘counting lines’, which in darkness were hard to distinguish from bat tracks.

In fact, between total darkness and the patchy bouncing light of our lanterns, my eyes were constantly re-adjusting, and soon every stop became another chance to me to trip. But later I realised how much I appreciated these stops, because not only were they a relief from the cave’s often overwhelming strangeness, they reminded me of its human factor, however ancient.  

Later that same day, I went to Seaton’s studio outside Ronda, where he showed me his recent work. Hanging across the long wall in two rows were eighteen paintings, each ‘drawn’ in pure pigments on vellum. Almost immediately, I recognised forms and distinctive colour combinations – ultraviolet, grass-green, ochre and black – from his Black March series made earlier this year.  

But I sensed something different in these new pictures, something more kinetic. My eyes ticked back and forth across the wall as I read them, first as a whole, then individually. I began to get an impression of echoes, patterns, even sequences playing out amongst their colours, forms and negative space. I asked him if the series had a title and when he replied “harmonics”, I was a bit embarrassed. It seemed so obvious.

Although I’d already sensed something, well, musical in the pictures, I was still a bit confused why exactly. Sure, artists have been blurring the edges between the visual and the musical since Pythagoras. But I’d always understood this as an appreciation of independent ‘sister senses’, not as hearing with your eyes. Besides, I’d always read Seaton’s work in terms of sculpture because to my eye, his approach to form and composition is apparently 3-D.

“Think about it though,” he said. “Music is something we see and feel as much as we actually hear, right? Otherwise, why would we dance?”

Looking again, I started to notice how certain shapes and lines repeat, like the bold black polygon that first appears in Harmonics I like an ancient floor plan. By Harmonics V, however, this shape becomes subsumed by other colours – vermilion, ochre, rose pink, verdigris – and looks more like a zigzag, an arrow, or a comb, forms similar to Pileta’s counting lines, or, as one of Seaton’s friends noted, letters from the Iberian alphabet. Later, I also thought of graphic scores by Stockhausen and animations by Walter Ruttman.

But any connection between Harmonics and early modernism (or for that matter ancient pictographs) would have to be coincidental, because not only does Seaton not use symbolism, he’s actually a musician.  

“The series really grew out of seeing music as vibrations. For example, black might have the lowest frequency, so that’s your bass. But if you take that black and put it together with four or five other colours to form a new shape, you describe a different space.”

I am not at all musical but can just about grasp that harmonies are based on tones, at least in western music. “So, you’re picturing vibrations?” I asked.

He shook his head, picked up a pen and started to scribble on the back of a receipt.

“Picture sound waves,” he said, drawing horizontal serpentine lines.

“We hear music because frequencies create waves of vibration. These vibrations react with air to form sounds, which we can hear depending on their frequency. It’s the number and size of these audible frequencies that form harmonies. So, we sense music with our ears, but it would never reach them without space and form, which are visual.”

As I sat on the sofa mulling this over, evening drew in and we swapped sunlight for electric. Looking again, I sensed another shift. I now noticed the vellum, its refined texture and how forms and colour seemed suspended in a grey zone between its surface and my eyes.  

“There are two reasons why I used vellum. First, it has wonderful ‘bleed’. Depending on how long I allow water to sit on the surface, I can control amazing effects and blur even the purest pigment.  

“Secondly, there’s the colour: that pale tan gives me a starting point for colour keys, and its neutrality makes forms seem to float.”

Harmonics aside, it’s practically impossible to be in Seaton’s studio and not think of music. There’s the usual dusty player and pile of CDs that like northern light or an old sofa feature in any good studio. But there are also actual instruments: an oboe and of course, Seaton’s clarinet.

“I’ve played it for most of my life. It’s just part of how I paint, and I love abstraction, improvisation. But I also like to work to Beethoven, especially the late quartets. There’s something so pure about quartets; each musician can play independently and still achieve harmony.”

We spent hours talking about the pictures, about harmonics, what it’s like to work with pure pigments. And we debated about colour and form. Do they mean anything in themselves? Or are they like notes or glyphs: unique but essentially meaningless unless they’re part of a greater system?

Later I thought of the cave and why I remembered some drawings more than others. I didn’t have any photos – picture taking is forbidden as flash causes light damage and upsets the bats. But I easily found photos online, especially of Pileta’s masterpieces:  a pregnant horse, and ‘The Great Fish’, which to me looked more like a seal. I also remembered an enormous snake, aurochs, and beautifully nuanced horses.  

But what really stuck in my mind was the endless ‘counting marks’. They were always in charcoal and appeared in clusters, often low to the ground or within a niche. Some looked rudimentary, just ticks and dots; others were more sophisticated, arrows, combs, possibly even birds. I had an immediate sense of the people who drew them, maybe working with children underfoot. Was this how they make sense of everyday life? Did these marks note how many animals they saw that day, what the sky was doing? How many of them went out, and how many came back?   

I think Pileta and its extraordinarily haptic sounds helped me better understand Seaton’s work. I’ve never been a musical person, and usually find related concepts confusing. But when I first saw Harmonics, on some level … I got it. Maybe my subconscious was still swimming with charcoal ticks and dots, giving me a language to help decode what I saw. I’m really not sure.

But Seaton’s pictures fascinate me. I even think they’ll tell me more, if I can find the right frequency.