Just going to ignore the above post and continue for discussions sake, this topic may be useful in the future.
Anti aliasing:
Step 1:

Here is a selection from your line art, you need to think about the information that these pixels represent.
Step 2:

Here is roughly the information the above pixels should be trying to convey.
You'll notice that even though the image is still broken into "pixels" the actual detail does not obey the restrictions, this is to accurately represent the information and basically how it should be received.
Step 3:

The image is now obeying the restrictions of the pixels, each pixel that from Step 2 that contained X% one colour and X% another is now those percentages put together.
This is perhaps the best way to sum up anti aliasing.
Step 4:


Cutting down on the colour count, there's no reason to have dozens of colours that are essentially the same.
This isn't the work process for anti aliasing, and the final product isn't ideal. This is just roughly how you should be thinking while anti aliasing.
It's not quite as simple as "adding buffer pixels" you need to know how many, what intervals the ramps may be at, etc, hopefully this has helped with that.
