How to dye yarn so full of color and life that it glows
Three tips to dyeing yarn with depth and dimension
By Brenda Lavell
This is written by the creator of Phydeaux Designs & Fiber; she is releasing a course on fiber dyeing that I recommend.
The first tip involves mixing colors of the same family or layering them imperfectly to create dimension to the project you are working on.
Shadows create dimension, and so using a gray can do the same for your yarn/fiber. (remember you can add but taking away is much harder).
*The entire article is fascinating and has a lot more tips and tricks than I put here. These are just my notes*