I have a colour video that I want to change to black and white. I don't know how to do this. I know how to tint it different colours, but that is not what I want. Thank you for your help.
Try this: Go into the "Video effects" dialog for the video object in question. In the "COLOR FX" section, click on the "Color Controls" button to show the controls for contrast, brightness and so on. Pull the second slider (contrast) all the way to the left. That should do the trick.