Black is not assumed to be a colour. Well, as far as Physics goes.
Black is just an absence of colour. It doesn’t have any specific wavelength like colours such as red, purple etc do.
Just as white is not a colour. White is a sum of all colours. It also doesn’t have any specific wavelength. When you pass white light through a prism, the light undergoes dispersion to give out a spectrum of many colours (commonly known as VIBGYOR).
So what do y’all think? Is black a colour? Why or why not?