Light and lighting in fashion and textile design generally relate to the viewing and production of a fashion or textile collection in daylight, or integrating LEDs, electro-luminescent wires, and optical fibres in the structures of fabrics to create a light-emitting fashion or textile collection. This ignores the potential that coloured light as material for design can bring into these disciplines. This paper aims to investigate coloured light as a material for design in relation both to physical environments and immersive virtual reality, and to develop design methods for fashion and textile design that could lead to a re-learning of coloured light as a material for design for developing novel artistic expressions. The first series of experiments focused on addressing the following questions in both physical and virtual reality: How do coloured surfaces and coloured light interact? How do interactions between coloured surfaces and coloured light influence the process of designing surface patterns? To critically examine the results of this research, textile and fashion design undergraduate students participated in a five-day workshop during which they experimented with, and reflected upon different types of interaction between coloured surfaces and coloured light in both physical and virtual reality. The students’ designs showed that the design method provided them with an understanding of the use of coloured light in their design processes through experimentation and individual exploration, demonstrating that this approach can make a fundamental contribution to the development of coloured light usage in various design disciplines.