What is Colour?
Visible light (VIBGYOR) or visible spectrum is that part of light (flow of photons) which is visible to naked eye. Or our eye can detect. Since light travels in wave, each wavelength defines a particular Colour and is unique.
SOURCE OF LIGHT - METAMERISM
As we all know, that the same Colour patch, appears different under different lighting /viewing conditions. Different illuminants such as incandescent light and daylight have their own special characteristics and the color’s appearance is greatly affected by these characteristics.
Different sources of lighting may make same Colour appear different under different lighting conditions.