Why is this blue color appearing I have a wave modifier on on object which has a couple of array modifier. i object , then an array to make it 10 , then an array to make total 100(multiply) .Then these 100 peices (one single)  have a wave modifier starting a empty.
The node map is 
As you can see there is some strange color at places where there is no emission shader. Why is it soand how to solve it.
The problem appears to be due to negative values being used in the Mix factor resulting in artifacts where the 'negative' of the orange colour is becoming evident.
Each channel from the Normal is in the range -1.0 through to +1.0 and so the 'add' can result in negative values. Normally a 'mix' factor will automatically clamp the values at 0.0 and 1.0 but in this case that doesn't seem to be happening. By enabling 'Clamp' you are limiting the output of the Add maths node to strictly the 0.0 to 1.0 range so that the mix is behaving consistently.