Colour sensitometry is the scientific method used to measure and evaluate the sensitivity of photographic materials, such as film or paper, to different colours of light. This process helps determine how accurately a material can reproduce colours under various lighting conditions and informs photographers and technicians about exposure requirements and optimal processing techniques. Colour sensitometry is essential in film development, quality control, and the design of colour-sensitive photographic products, ensuring consistent, accurate, and high-quality colour reproduction in both professional and artistic photography.