CA Process

In my last post i explained Chromatic Abberation. Well i did have enough time to go through how to actually do it.

Adding Chromatic Abberation:

2D Addition

I've made a rough composit of a CA process on a still, mind you this process is more manual than i usually use, also i base it more of a shot by shot basis. I have a Gizmo i use in nuke that saves me a large amount of time.


The reformat simply changes the format so ignore that. Basically each shuffle node pulls out the seperate rgb channells. Then the red and blue channells have a god ray applied scale, after this ive merged the channells, so first red and blue then merge the red/blue to green.

The result is very slight, but it helps add to the subtle edges to the image.



3D Addittion

Now this is slightly more tricky. So start by setting up 3 different renderlayers RED/GREEN/BLUE. Render your image with its intended Refractions, this is now your green channell. Now, increase the IOR (Just remember to note down your IOR) of your reflections (a small amount is all that is needed, but you'll need to play with your settings yourself) this will be your red channel. Lastly reduce your IOR from the FIRST IOR, this last channell is your blue.

Your results should looking something like this.



Now to display how to easily merge the 3 channells. Ive decieded to add all the channells to black, but this can be done easier (this uses more nodes than it needs).


The shuffle pulls the r,g,b channels out of each of the images. and then they are merged over black.


This merge method is a little bit lighter on the nodes but also simpler. The first merge adds blue too green, then the second merge adds red to blue/green. Overall the result is the same.


Left: Chromatic Abberation Refraction - Right: Standard Refraction


Once again the result is quiet small but the overall effect helps tp sell the shot. These effects can be replicated in AE and any other compositing software. Hopefully this answeres any questions....