flashing backgrounds

I have created a site containing 3 frames: side, top and main. The background colour for all 3 is set to #333333. As the side loads, there is an unpleasant flash in the main frame, as it appears white before switching to #333333. A similar effect occurs on another page where I have created a small iframe - again the frame shows white before the htm page loads into it. Is there any way of losing this unpleasant effect?