Combining Render Layers in the Compositor

Hi guys,

I’m currently working on a short video file - rotoscoping a lightsaber effect. This worked fine last time, but this time there are two different colours. The colour effect is applied in the compositor, and I don’t see how to get the relevant empties to the right colours and export. I have each on a separate layer and render layer, and I can get the composite node to show up correct and as expected, but how do I export the contents of this, as the rendered image shows up as a white, lightsaber-shaped box over a black background :confused:

I’m using 2.5.3 if it makes a difference.

Sorry, noob question and I really should know this, I’m sure :frowning: