I have yet to get any paint to stick to bare foil very well, What I do is coat it with Future floor polish which sticks to the foil very well, then paint over the future, acrylic, enamel, what ever, even water colors. Now to tint the foil may I suggest tinting the future with the acrylic color of choice then applying it to the foil. I have never tried this but see no reason why it wouldn’t work for ya.