Firstly open up the image you wish to turn the lights to have a rainbow effect. I'll use a Ford Focus Cabriolet.
Right now create a new layer and select the 'Elliptical Marquee Tool' and set the feather to 5px.
Once that is done go to gradient and go to the drop down box like so and select the Gradient that i have highlighted in red
Once you've done that select the Elliptical Marquee tool and go round and make a shape like this one I've done.
Now select the gradient tool (MAKING SURE THE RAINBOW GRADIENT IS ACTIVE.) on the new layer, stretch it from one end of the circle to the other end. If done correctly it should look like the following pic.
Now that is done we can work on the next light. Using the Elliptical Marquee Tool make another circle but smaller so it fits the light.
Now you can add the rainbow effect, again using the Gradient tool. here's what it looks like. (Make sure its the same angle as the other light.)
We can now change the Layer blending mode and opacity. So it looks more realistic. Blending Mode: Multiply & Opacity: 27% (Although this may vary on cars. Do so until you get my effect.)
Now its time to flatten the image, Go to 'Layers' >> Flatten Image.
Finished product FULL:
If you require any help email me on
boroboyben2007@hotmail.co.uk
Please note: I've accidentally forgot to add the other gradient but if you do need help email on the above address. Or add it to msn.