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Light is made by photons having different wavelengths. Each wavelenght in the visible spectrum is associated, by our brain to a color. When photons of each visible wavelength are mixed toghether we perceive the light to be white.
When this white ray hit a surface part of the wavelength will be absorbed, while other will be reflected depending from the material of the surface. The mix of the reflected wavelengths will be then perceived as a color. If all the wavelengths are absorbed we will percive black, that is no ligth.
Most things as explained by other members. I just want to comment regarding black light, I am not sure what you mean here by black light. Are you referring black as one of color as light?
But, indeed we have black light as ultraviolet light (UV-A ). The name could be misleading sometime.
Yes you are right in general we could also include infrared and ultraviolet radiation in the term "light". However the term "light" is usually referred to the EM wave falling into the spectrum of frequencies (or better wavelengths) visible by the human eye.
I think, given a part the EM spectrum we can define "black" the absence of EM radiation having frequency inside the part of spectrum we choose.