Comments If you have multiple layers in a Layer Group, instead of setting each layer’s blend mode individually, try setting the blend mode for the Layer Group. This will treat all of the layers in the Group as if they were “merged” together, then blend them as one.
In the first example each individual layer has it’s blend mode is set to Multiply. In the second example, each individual layer has it’s blend mode is set to Normal, but the Layer Group is set to Multiply - as you can see the results are very different.
The same is true with other blend modes:
http://blog.martindoersch.at/2009/06/bubbles-2/
Just create some layers with some bubbles (brush) and set the group which contains the bubble-layers to vivid light (or experiment with other blend modes).
Martin