Mixing Well Demi Permanent 9CB AND 6N - Create Mushroom Brown Hair

Created my own dark mushroom brown demi permanent hair color using Wella 9CB and Well 6n Demi permanent. I used 1:1 ratio of both colors and added the necessary amount of 10 volume well developer in a bottle applying to dry hair. Left on for 30 minutes rather then recommended 20 minutes. It did not do anything negative to my hair as I was going to dark. Liked the results and was easy.