I have the magix movie edit pro mix plus and would like to know how to turn the background colour of my movie into other colours such as black and white. Can anyone help? :)
Right click one of the objects on the timeline and from the pop up menu select Background design, Background design, a window will open with various options. Choose the one you want and the appropriate Apply button.
I think what you want is (Secondary) Colour Correction found in the Video effects tab of the media pool.
See MEP Help> Index> Colour Correction. By selecting the different colours in the background a mask forms, then you can change them to Black and white using the Saturation slider, or other colours using the colour wheel.