Color Photography Explained-5
In this picture the green and blue-violet separations, last shown, are here superimposed in their complementary pink and yellow. It is possible to gain the same effect by recomposing the original colors of the separation, but for several reasons this is not the most practical method of operation. One reason is that the separations such as the last three shown are really negatives and by printing the negative in the complementary color the result is theoretically the same as would be gained by printing a positive in the original color.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 12 Chapter 6