Render looks Cartoonish and not realistic

Good Day. I am rendering a logo and while it renders it looks perfect but when it is done it looks as though a cartoon filter is applied. It’s as if the quality or resolution suddenly drops on the last render pass.
I am rendering out 1920x1080 at 100%. Samples are low, render at 24 and preview at 12.
Im not sure what the other settings are supposed to be. I am using Blender 2.72 and have 4 layers selected. I am new to blender so I have followed lots of tutorials but when you have to apply what you see in a Tut to your own model it starts getting complicated.
Please help.

Screenshots of a before and after (ie good as it’s rendering and then the cartoon look) will be needed to help, plus maybe a blend file

Hi. I figured it out. It was a little button called ‘Freestyle’ It seems to apply a Line over all the edges and this makes the rendered scene look like it has a cartoonised effect to it. Like what you would see in Manga or Stylised effects through Photoshop.