Hello shravan,
A surface appears black when it absorbs all the incident lights upon it.( Light means all colours in the range Violet to Red).
If a surface reflects red, it would appear red. If a surface is black, then it means, it has all the colours and we cant see them(does not reflect anything).
I have noticed while colouring pictures that the colour we get when we mix all the colours is BLACK.
That was why I wrote that black includes all colours.
You wrote about DARKNESS actually and not the BLACK colour.
It is true that darkness is the absence of any light. But black "colour" is a colour only.
Where did you get that nothing and everything are the same?
Hope you are not an anti-Krishna.