After 14 hours of rendering on a quad core qx 6700, I made two ambient occlusion and z-depth passes. The ambient occlusion passes had different radius values and were merged into the image using Photoshop multiply layers.
The first z-depth pass was created to make a small DOF in the foreground. Then it was used as a Photoshop filter. The second z-depth pass was created to make the fog effect. I then applied a Photoshop hue and saturation adjustment layer and moved the lightness value to 10 and applied the depth picture to the layer channel.
This is an easy way to create a fog effect to provide depth. A fifth pass was made for the letters so that I could have a selection channel to adjust the letters in post production. You can see letters are more noticeable in the final picture than in the original render. Several color correction adjustments were made as adjustments layers using masks to hide and show the variations in different areas of the picture. You can see highlight colors change throughout the image.
I also created an alpha channel, and selected the white parts of the image using a color range selection). To get a film effect I applied a Gaussian blur (glow effect) and "hard" chromatic aberrations. This effect can clearly be seen in the letters in the lower left area of the final image. I added color to the glow with a colorize hue tool to give the glow a "yellow" sun effect on the bright areas and on other areas to get vivid colors in the highlights.
I added people with slight color correction and blur effect to a few of them. I did this using common commands with a Wacom tablet. Finally I flattened and applied a sharpen mask effect, added a few more color aberration and a vignette (lens distortion filter).
