It's pretty dark, when you comp that onto it's going to really darken the entire frame. Did you pipe in the AO into the ambient colour of a lambart? If so, make sure the lambart colour channel is white.
Thank you , for the advise! :D
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I would try a surface shader with the 'out colour' set to the AO.. It takes away all of that grey and just leaves that contact shadow. This is how how Jin Zhi the masters lecturer does this, and how it is achieved within the industry. Really would advise this.
Example of this:https://docs.google.com/file/d/0B5xy60suVxIHWkxjSUZiVG1OejQ/edit(Hopefully this link works.)
At the moment we are going to give it a goal and do some compositing and see how goes because the render is finished but thank you for the advise if we have to render again. :D