Is the disney example really demonstration of an imaginary colour? 

To me, it sounds more like that old optical illusion where a checkerboard has a shadow thrown on it, such that the same middle shade of gray looks darker and lighter depending on whether it's surrounded by bright or by dark colours. As in, the grass looks greener because it's more different from pink, than because the pink is fatiguing your red and blue receptors. 122.106.155.219