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Above is a collection of photos that I've taken over the last 12 or so months using a method called "Light Painting". This requires a camera on a tripod, a light source (in this case, sparklers) and setting the camera to long exposure. A remote shutter is definitely recommended for this as you're actually walking around the car shining your light source close to the paint work. Any imperfection you don't want showing up, simply shine your light source elsewhere and it won't highlight it in the final photo.
I happened to stumble upon using sparklers after seeing an image online and wanting to recreate it. They're pretty cheap (you can pick up a 24 pack for like $3 from the Woolworths party section) and the results are so incredibly unique. Your ordinary light painting is already pretty challenging, however light painting with sparklers is actually a lot harder than what it looks, and you really have to know how your camera works in order to capture the clearest photo possible. Too low an f/no (or depth of field) and your sparkers and subject matter will be too dark. Too high and f/no and your sparklers will be suuuuper bright and potentially out of focus (due to the shallow depth of field).