For the last five years I've been working in the VFS industry, so post-production is my daily bread. Like a lot of the world, I use Nuke for post-processing and for this scene it was fairly simple, as you can see on Nuke's tree (Fig.18).
I always render to 32bit EXR format to have full control over the render in Nuke. My passes were just beauty and ID mask. I made a few color corrections and added local masks to highlight some areas. Then I adjusted the glows on the LED diodes and smoothed a little glow over the whole image. I decided that it needed a little bit more atmosphere, so I decided to add some dust particles. The simplest way to do that was importing the camera to Nuke and using its particle system with proper ZBlur to create the dust. I also mixed it with a dust photograph to make it more real.
Finally it came time to add a well-known combination: chromatic aberration, vignette and grain. I always caution people to use this combination wisely as it can help your image, but can just as easily destroy it. Just observe normal photos and that should help.
Here's a comparison of the pure render and the final image (Fig.19).
And here's a larger version of the final image (Fig.20).
Fig.20 - Character design © Sony Pictures
Finally here comes the end. I have special relationship with this poor alien; we spent about five years together from the beginning of this project to the end. I'm really happy to see him finished – there's one less skeleton in my wardrobe. I hope you've enjoyed my Making Of and feel free to contact me with any questions at firstname.lastname@example.org