Editing againnn

So I've found some clips to create a "camera light leak" effect, but unfortunately, with the base colour of those being black, it cuts out the rest of the footage when overlapped. I've tried to correct this by using the brightness and contrast wheel on the base footage, along side the 'arithmetic' effect by using an orange tint. Although the footage now is dimmer than previously desired, I think if I can edit all the factors enough, I might solve my problem.