Sounds like a graphics prob to me but I'm sure techno peeps will be able to help more than that. Have you tried apple help forum, they are usually very good?
There are countless posts on loads of forums which suggest iPad colour faults can be fixed by simply slapping it firmly on the back. (Perhaps it's choking?) Proceed at your own risk!!!
Alternatively you could try resetting your iPad to its factory settings:
Press and hold down the iPad's "Sleep/Wake" button and "Home" button simultaneously. ...
Wait for at least ten seconds for the Apple logo to appear on the screen. ...
Release the buttons and wait for the iPad to restart.