Strange Renders

Hi all,
Could any one tell me why the second render (taken after UV mapping for the board) is soo much lighter than the first early render?
http://www.freewebs.com/concept3d/FWThumbnails/Diffrences.jpg
I think it may be something to do with me trying to change the background…
Thanks,
Concept 3D

Sorry for double post :frowning: