I didn’t know that players are unable to dye armour in WOW.
Meanwhile, I’ve been experimenting with dye-mixing for my character’s Necromancer’s Armour in Guild Wars. It comes in red by default, but I dyed it blue soon afterwards. I got bored with blue, so I decided to try another colour. The dye I used for each of the four pieces of armour here was a mixture of one Vial of Orange Dye and one Vial of Green Dye. It makes a sort of dull bronze shade, which I think looks nice. This screen capture was taken at the character selection menu: