White light itself consists of 7 colours i.e. VIBGYOR
V - Violet
B - Blue
y - yellow
O - orange
R - red
These are the colours which white light is consists of , it can be checked by prism experiment whereas black
itself is not a colour , When there is no light the black colour forms , i.e. you can take example of a room , When there is no light room is dark or black .