In optics, light caustics are patterns formed by the concentration of light rays reflected or refracted by curved surfaces or objects. These patterns appear as bright curves or surfaces where light intensifies, often exhibiting cusp-like singularities. Common examples include the shimmering lines at the bottom of a swimming pool caused by sunlight refracting through water waves, or the bright shapes seen when light passes through a glass of water.

The term “caustic” originates from the Greek word καυστός (kaustós), meaning “burnt,” reflecting the intense concentration of light in these patterns. At the bottom of this post you will find a video shot recently in the studio that clearly demonstrates the phenomenon.

In computer graphics, simulating caustics enhances realism by replicating these natural light patterns. Techniques such as photon mapping trace the paths of photons as they interact with surfaces, accurately rendering caustic effects. In my own work, I recreate these phenomena physically in the studio using custom lighting units and specially designed black water tanks. An extensive filtration system is used to achieve the crystal-clear conditions required to create bodies of work such as Vanitas and Rosae. Using a brush, spatula, or my own hand, I am able to quite literally paint the subject in light. This interplay of light and shadow evokes the chiaroscuro of the Dutch masters, yet the underwater setting introduces suspension and impermanence, pushing the imagery firmly into a contemporary context.

‘Isis Bound’ from the Vanitas series (2008–ongoing)

Understanding and replicating caustics is essential in fields ranging from visual arts to optical engineering, as they play a fundamental role in how we perceive light interacting with materials and surfaces.

The artistic legacy of light caustics: a historical perspective
Light caustics — shimmering patterns formed when light passes through or reflects off water — have fascinated humans for centuries. These ephemeral shapes evoke wonder and beauty, functioning both as inspiration and metaphor in art. For contemporary artists, working with caustics created through water bridges science and traditional aesthetics, echoing themes rooted in historical masterpieces.

The precedent of light in classical art
The interplay of light and water captivated painters throughout the Baroque period. Artists such as Caravaggio used dramatic chiaroscuro to emphasise light’s transformative power. While Caravaggio did not depict caustics directly, his treatment of light as an active force resonates strongly with the way water refracts and concentrates illumination — a phenomenon I have continually explored.

‘Glass: plate 0533’ demonstrating the use of light caustic patterns in water

Similarly, Joseph Mallord William Turner — often described as “the painter of light” — explored reflections and refracted light on water’s surface in works such as The Fighting Temeraire. His paintings evoke the transient beauty of light, prefiguring the fascination with caustics in modern art.

Impressionism and the dance of light
The Impressionist movement further deepened the relationship between light and water. Claude Monet’s series such as Water Lilies and The Houses of Parliament captured sunlight interacting with water in flickering, almost caustic-like effects. For Monet and his contemporaries, water became not simply a subject but a medium for light itself.

Optics and surrealism
In the twentieth century, artists such as Salvador Dalí explored light as both a physical phenomenon and a psychological symbol. While not directly concerned with caustics, Dalí’s distortions and reflections invite a dialogue about perception that aligns closely with optical phenomena.

Contemporary art and light caustics
Incorporating light caustics as a medium places contemporary artists within this long lineage. Caustics possess a transient, meditative quality that resists digital perfection, offering an analog and almost primal connection to physics and nature. This lineage also includes László Moholy-Nagy, whose Bauhaus-era experiments with light, shadow, and photograms paved the way for light itself to be treated as material.

Conclusion
From Caravaggio’s chiaroscuro to Monet’s shimmering waters and Dalí’s distortions, artists have long sought to capture light’s interaction with the physical world. Contemporary work with water caustics carries this legacy forward, blending scientific precision with aesthetic wonder. At its best, this work becomes a bridge between the ephemeral and the eternal.

Working with light caustics and their effect on carefully constructed underwater scenes has been a lifelong obsession. Please explore the ARTWORK navigation above to view four decades of these experiments.

See available ‘Glass’ works here.

EDITORS NOTES...
Several works produced during this body of research are available for rights-managed editorial and institutional licensing through The Legacy Collection, Hamilton’s long-running photographic archive.

https://www.distilennui.com/collections/the-legacy-collection-rights-managed-image-licensing