Purple and Gold Canvaswork Gradients

A major part of my research investigating color interactions in metal embroidery is posing the question "what is gold's complement?"  I think it is an easy thing to assume that we can substitute yellow for gold but does it really interact the same way with the other colors?  We all know that the texture and surface of a thread can change it's appearance and affect on the composition but what happens when it moves from "shiny" to "metallic"?  Is gold metallic yellow or is gold a separate color to itself? 

I thought a good start was to stitch gradients moving from purple to gold.  If yellow can substitute for gold, then purple, as the complement of yellow, should also be the complement of gold.  This means that in the gradients, we should see a desaturation of both happening as they move towards the middle of the gradient.  So, can gold desaturate or "dirty" the purple and can purple desaturate or "dirty" the gold?  Additionally, using these samples, I can address the effect of stitch pattern to color perception.  

Some of the different gradients in the different canvas stitches.  These are all 1" x 1" squares on 18 count canvas. 

I'm working the gradient by row with the last column being the same stitch- Upright Gobelin. 

Another exciting discovery in this exercise for me was learning how to do a Sorbello Stitch.  I was watching Jan Beaney and Jean Littlejohn's DVD In Stitches while I stitched these the other night and I loved what Ms. Beaney was doing with the Sorbello Stitch so much that I decided to try it out.  I LOVE this stitch!  I love the texture and I love the movement of actually executing the stitch.  Will be using this stitch a lot more in the future and I'm curious what it would look like if I used some stretched purl or passing.