I downloaded a transition template from Motion Array - it's supposed to look like a polaroid picture. It worked properly three times on three different video clips (white border, black background and then the image in the centre) but now if I add it to any other piece of video, the black part is now white and it's just all white around the centre image. All of the parameters I used are the same as the previous clips and my base background is already black. I don't understand what the problem is. I have tried changing the colour of the transition but that just makes the entire frame one colour. I need it to have a black background and a white border like it originally had. Any ideas?

I've attached one of our FCPX courses to this thread that focuses on graphics & transitions [videos 16-19 are the ones that cover transitions] -- maybe there'll be something in there that will point you in the right direction, or perhaps another FCP user/expert will have a suggestion to offer..