Let's write about when VBjin force dumps in Anaglyph, even though you want to dump one screen only.
Also known as
The Red Alarm Effect:
What you want to do is split side by side.
So now you have a Red screen and a Blue screen next to each other, unless you chose Greyscale, which is also fine.
Now after you complete the avi dump, make sure you crop 400 twice (Assuming you have separation at 16), so both colours have their own screen.
At this point you'd realize, that you can't use the normal levels version which feos has provided (from me).
That code only works for pink dumps.
For Red screen
Language: avisynth
Levels(0, 1, 124, 0, 255).Levels(0, 1, 254, 0, 255)
For Blue screen
Language: avisynth
Levels(0, 1, 47, 0, 255)
Now those that used Greyscale for dumping use:
Language: avisynth
Levels(0, 1, 255, 0, 157)