Another way to color bulbs is glass paint. You can get a small bottle form any craft store, and i'd guess in the craft section at Wal-Mart. It comes in many colors, and all you have to do is dip a small bulb in the jar, or paint it onto a larger bulb. Repeated coats produce deeper colors but less light output. I did this years ago to get the lights in my after market gauges to match the stock gauges in a Mustang I once owned.