"Nobody makes a yellow 9006 in quality worth buying. If you're trying for yellow fog lamps, the stick-on films don't really tint the light very effectively. You can get good results by removing the fogs, cleaning the lenses *thoroughly*, and spraying them with several coats of Dupli-Color Metalcast yellow, which is a transparent yellow paint product:
http://www.duplicolor.com/products/metalcast.html . Let each coat "flash off" (dry most of the way) before applying the next, and use thin coats so you don't get drips and "sags" in the wet paint. With each
successive coat, the yellow tint will grow deeper. Make them about 2 shades deeper than you think looks right, and it'll turn out well in the end. Of course, the coating needs to be permitted to dry and harden completely before you take the fogs out on the road, otherwise dust and grit will become embedded in the still-tacky surface."