Fading Colors Out

hi,
So i’m still fairly new at all this…i’ve started practicing on myself and my one really good friend who has graciously volunteered to let me practice (ive also done the practice skins.) She wants some paw prints with colors going from a solid darker pigment to a lighter “faded out” look. Would you suggest doing a grey wash first then color over top? or just use the solid color and mix white to lighten it up as the tattoo goes? any advice would be appreciated!