Photoshop layers and drop shadow question

[Jon_King]

I am working on a multi layer image and I have all layers with a drop shadow but I don't want the shadows to cast onto the background layer.

In other words, all layers shadows interact with each other but I don't want any shadow on the background layer. Any thoughts?

[john_k]

Create one new layer with a white rectangle covering the entire area. Add a copy of all of the objects. Then do a knockout/punch so that the rectangle has a hole in it corresponding to the overall outline of your objects. Put this layer on top.

There may be a smarter way, but this will do the trick.

[Jon_King]

Thanks john_k!