Light sources have spectra
Sunlight, LEDs and other sources do not all contain the same mix of wavelengths.
Pigments subtract wavelengths
A pigment looks coloured because it absorbs some wavelengths and reflects or transmits others.
Screens add light
Displays combine emitted red, green and blue light in varying amounts.
Perception is contextual
Surrounding colours and adaptation can change how the same physical stimulus appears.
Source trail: NASA: electromagnetic spectrum
This page explains scientific concepts for general learning. It does not replace laboratory safety procedures, professional engineering guidance, or individualized medical advice.