I'm fairly new to Flash, but I'll give this a go...

Create a square (rectangle) the size of your canvas--make it a symbol, put it as your bottom layer.

Then you can create a Keyframe (Motion Tween), right click on the square---> properties-->Color effect-->Tint. [if you cant right click, then go to Modify->Instance->Color Effect->Tint]. Then select the color you want it to change to and the % of change.


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_chris___