We now open a new file that will be used as a background. This is an image I took of Artists Point while on vacation at Yellowstone National Park.
	We place the background image in a new layer beneath the layer that contains our model.
	This is the result so far... but we are not done. I usually do a little careful erasing with the eraser tool using a very small brush at about 10% opacity around the edges. I picked up this technique watching a documentary on Star Wars: The Empire Strikes Back. ILM composited many of their shots at 90% opacity to help mask the sharp outlines of their images. I have modified the technique so that I only modify the outline. This keeps the center of the image looking very solid while merging the model nicely into the background.
	Next, I make a duplicate of the background layer and active the top most of the two layers. Then I use the Motion Blur filter to blur the background. The intention here is to make it look like the hot engine exhaust is distorting the background. I used a very high distance setting and a nearly vertical angle. Once the background image is blurred, I carefully erase most of the blurred background except for areas around the engine exhaust.
	Finally, I create a new layer on the very top. This is the "Special effect layer". I can make modifications to this layer such as adding lens flares, and environmental effects without screwing up the background or the model on previous layers. Note that layer 3 is the unmodified background layer, and layer 4 is the blurred background. You can see the parts of layer 4 that were erased.
	Now I select the paintbrush tool and prepare to add my "special effects".