Another step that might seem counterintuitive is the addition of black highlights. The effects become apparent toward the end of the flame process. For this, the positive stencil should be used to apply lightly sprayed subtle black outlines in the interior of each flame. We strayed from the instructions and freehanded this step-using the stencil would have been better. Black is the only color not included in the paint set, so we used some black Rust-Oleum thinned down with acetone.