World background settings completely ignored when animation is rendered

Hello everyone, I’ve been dealing with this issue for the whole afternoon and I’m getting mad but I can’t find any real help online. Hope you know something more about it.
I’m basically using a title template and I want to create an animation displaying some text and some moving objects. I did everything but all of the objects my project uses are on a transparent background. I want the final video to have a plain white background. So I went to the world tab and changed the Horizon color to white, the Zenith color to White and the ambient color to a blueish one which is the color of the text. I’ve tried to render with Paper Sky, Blend Sky and Real Sky. I’ve also tried to add a background plain white image (in the 3D View Properties tab, the one that pops up when you press N if you are in the 3D view panel). I also went to the Texture tab and added the same white image both as a world texture and as a “Texdraw” texture. There’s white everywhere! But everytime I render the animation, it comes out with a greyish background! I can’t understand why! Can someone please help?