Strictly speaking, there are no colors in nature, only electromagnetic radiation. In the visible spectrum, it is called light.
One can imagine light as a wave. Sunlight is a mixture of many individual wavelengths that together appear as white. Each wavelength in sunlight has a different color. Short waves are blue; long waves are red. By its nature, every surface reflects certain wavelengths better than others.
If a surface reflects only short waves, it appears blue to us. If it reflects only light rays of medium length, the surface looks green, and if it reflects only long waves, we see red. If a surface reflects rays of various lengths, then we see yellow, orange, purple, pink, brown, light blue, and all the other blended colors.
Colors are perceived as energy-radiation by the human body. As long as 3,000 years ago, Chinese doctors treated the sick with colors.
Professor Nils Finsen, who in 1903 won the Nobel Prize in medicine for his research into light and color, offered scientific evidence. As the founder of science-based phototherapy, Finsen established that colors are autonomous forces that cause significant responses in human skin.