PSD (post-Processing): -
Preview shows images with post processing, not raw renderings.
For newer versions of Corona Render , click reset settings (in Corona Renderer itself) to display the content correctly during rendering.
I should notice that this scene itself doesn't give you some full understanding of working process. The scene is made with the help of some aspects and algorithm which my course "CGBandit "containts. But it might be interesting for you to analyze and test it.
Corona Renderer 3. 3D max 2015