For centuries, ultramarine was valued more highly than gold. Even today, it remains a colour that carries depth, memory and quiet intensity.

Watercolour is often seen as a traditional medium. Yet every new pigment, every new surface and every unexpected reaction opens another territory waiting to be explored.

What can twenty-six years of waiting teach an artist? A personal reflection on Christo and Jeanne-Claude's The Gates—and why time may be the most important material of all.