hey i have a blue roan i use : shaws
black coat shampoo. for grey black or mainly black dogs. from petsmart i think i got it .
and on the back it says for black,blue, grey and charcoal dogs , and any of these with white patches,
It has the address here
Shaws pet products ltd
Aylesbury,bucks
Hp19 8rb
I dont use human shampoo but i do use the conditoner