Take a look at how I adjusted this occlusion pass in Photoshop (Fig.06). The final image will have this as a Multiply layer on top.
After compositing the layers, you can desaturate the whole image and increase the contrast in Photoshop in order to see where the important areas are and how the contrast is balanced in the image. Take a look at Fig.07 to see the balance between light and dark areas in this image.
The floor and background are very important for characters, and I always try to put characters in a cool environment. In this example you can see that I used lots of boxes with a metal (lume) in the diffuse colour slot (Fig.08). Some boxes are clearer than others in order to give more contrast and balance. I used a plane in the background with a texture to be reflected on the boxes; this texture was the same that I put in the final image.
For this piece I actually used a background from another artwork that I created, but it could have quite simply been a photograph (Fig.09). The coolest thing about it, I think, is that blur which helps to bring the characters in the foreground out even more.
The choice of the colour I used in this work was primarily to enhance the look of the girl. As you can see, the two boys are looking at her, so she is the centre of the image - as is the red colour which is different to all the other colours used in the image. I desaturated the image a little in order to achieve a more realistic look, keeping the main colours of the scene: green and red.
And finally, here you can see the difference between the original and render and final image with a background (Fig.10). It's cool to see what we can do with some of our old 3D models. Don't let them die on your hard disk - get them out and reinvent them!