In additive colour theory (light frequencies), white is the presence of all colours and is, therefore, a colour. Black is not; without light everything is black.

However, when thinking about colour in terms of physical pigments (which is subtractive colour theory), the opposite is true: white is not considered a colour while black is the presence of all colours.

In traditional colour theory, black and white are not colours at all.

In our psyche, black and white are opposites. Black traps space, white opens it up. The use of the two together is an attempt at balance.

This portal concealed in the blackness could lead to.... ?