opposite sides

So if we were to take a wave diagram with equal apexes and minimum resting points one could ascertain that any part of the wave is equal to any other part parallel to it EXCEPT on opposite sides of 0(N) i.e X = X(oppositeN) so therefore by equating this to colours we can assume that X = -X e.g black and white and N would hold a neutral point regardless of the colour spectrum(white= 1st, black= last, grey=2nd from last e.t.c).Though by accepting this we are also accepting the possibility of a negative colour spectrum where white holds the last position and black holds the first, while N stays constant. so by this standard assuming the plausibility of a definite answer rather than + or -, what position does the colour gray hold? (being that unlike the colour white or black which are absolutes and will readily change into eachother when negated whilst the other colours may change to completely different ones)