Hi all,
I am currently practising render passes and layers and what-not. I created a seperate render layer which will only capture my shadows using the "use background shader" technique.
When I compose the shadow layer over my colour/diffuse pass, I am getting unusual extra artifacts. you can see this on the cylinder and the stripped ball. Also the shadow do not go all the way down on the red ball....

Please let me know what is causing this and if there is an easy fit to it.

Thanks