Chasing Light: Painting a Double Rainbow

Some paintings begin with a sketch, others with a fleeting moment. This one began with a photograph taken in the Northern Territory sixteen years ago.
I had painted the same scene several years ago, but recently I felt drawn back to it. Looking at the photograph again, I realised there was an opportunity to explore something I had not attempted in the earlier version: a luminous double rainbow stretching across the sky.
Rainbows are fascinating subjects for painters because they are not physical objects. They are simply light interacting with water droplets suspended in the atmosphere. Their beauty comes from their transparency, making them surprisingly difficult to paint convincingly.
A rainbow forms when sunlight enters a raindrop, bends (refracts), reflects internally, and then exits the droplet. This process separates white sunlight into the familiar spectrum of colours. A double rainbow occurs when the light undergoes a second internal reflection before leaving the droplet. The result is a fainter outer rainbow with its colours reversed. Between the two rainbows is a darker band of sky known as Alexander's Band, a subtle but important feature that helps create the illusion of realism.
Capturing these effects required patience. Rather than painting the rainbow directly in one session, I built it gradually through multiple transparent glazes. Each layer adjusted the values of both the rainbow and the surrounding sky, allowing the colours to appear luminous and integrated into the atmosphere rather than sitting on top of the painting.
The work was painted on a 60 × 45 cm canvas panel with multiple layers of acrylic ground. I began with a transparent red oxide imprimatura to establish the major value relationships before moving into a low-chroma block-in. Keeping the initial colours subdued allowed me to control the overall harmony of the painting and reserve the brightest notes for the final stages.
The foreground features three cattle, including two Brahman cattle. These animals are iconic in many parts of northern Australia and are particularly well adapted to the harsh climate. Their calm presence provides a visual anchor within the composition, balancing the dramatic atmospheric effects overhead.
As the painting progressed, I focused on strengthening the relationship between light and shadow throughout the landscape. The large gum tree became an important structural element, framing the scene and leading the eye towards the river and the rainbow beyond. Textured impasto passages were used selectively in the foreground, while the sky and rainbows were developed through softer glazing techniques.
One of the aspects I enjoy most about landscape painting is the challenge of translating fleeting natural phenomena into permanent form. A rainbow may only exist for a few minutes, yet through paint it can be preserved and experienced again and again.