The three images today are actually three versions of the same digital file. I shoot all my images digitally and have my camera set to create a RAW file of the scene. A perfectly exposed RAW file doesn't necessarily give you an accurate representation of what you were looking at but it does give you most of the information to re-create it accurately. Then again, what law says you have to re-create it accurately and besides, you only have your memory of what it looked like to go by now. More than ever, the final image has become your interpretation of what you want it to be. The new version of Camera Raw has an abundance of adjustments that can be made before you even open an image up in Photoshop. Color balance, color saturation, contrast, shadow detail, and many others are all under your control.
These images were made during a 30 second exposure where I gave each car a pop of a flash with a red gel in front of it. The top image is close to the way it opened up in Photoshop without many changes in Camera Raw. On the second one, I adjusted the color balance in CR to neutralize the red cast from the flash. This added blue to the sky, which I liked. I did want some of the warm cast back in the cars, but at the same time I didn't want to lose the blue in the sky. The bottom image was created by combing the first two images. Image one was added as a layer in front of image two. I decreased the opacity to about 58% in order to allow some of the neutral color of the bottom layered cars to come through. I then masked the sky so it was about 85% the rich blue of the bottom layer.
This is a great example of why photography is art! I controlled every aspect of the creation of this image from the time of day, the composition, the light, and the final color. The camera only did what I told it to do, and nothing more.