Hi,
Sure this is easy for your professionals out here...

I have a logo which is white text and a colored coin on a black background.

I want this logo to scroll over a background film clip.

Please, how do I get rid of the "black box" around the logo? I want the black to be invisible over the background.

I tried Video Filter "Image Mask - Channel Luminance" and it nearly works but the coin will get a bit of opacity. The coin and white text should appear natural and solid over the moving background.

Thankful for any help. /Johan

Effects, Key, Luma Key, Key out Darker, Try that.

Thank you Mark, you answered faster than the time it took for me to check my post! Exactly what I needed!! Hope I can help you another day ... /Johan

Johan, FWIW, I have always achieved better results when I separate the elements of a logo in Photoshop and then import the resulting psd file into FCP. It shows up as a composition with the layers on their own individual tracks. Then you can just copy and paste the tracks you need over your footage.

If you don't have Photoshop, then Mark's suggestion is the way to go.