Alpha in render (nearly) invisible

Support Lighting and Rendering
1

Hello.

I am making a simple scene and would like to make the background in alpha - meaning transparent enough that I can composite an image behind it and that ends up being visible. currently the glass is so dark I can’t see the composited background image trough it.

I am working in exr, does that help?

http://www.pasteall.org/blend/35252

2

I see… I saw those posts before but didn’t get the similarities. Thanks.