Here is a photograph of Laurel, taken against a white seamless background in a studio environment:
I wanted to replace the white background with this spotlight background:
To do so, I of course needed to mask out the white background which I did with ReMask from Topaz. The Layers Panel in Photoshop looks like this:
Next I placed the spotlight background under the Extract layer, transformed it to fit the frame, then I combined the bottom three layers into one layer. For trick #2 to work, this Background layer of the retouched model at the bottom of the Layers Panel is needed. The Layers Panel now looks like this:
Here is what the image looks like at this point:
Some of Laurel's beautiful hair is definitely missing. Here is trick #1 to get it back: Make sure the top layer is active, and click on the layer thumbnail to select it. Go to Layer -> Matting -> Color Decontaminate... and drag the Amount: slider to 100%. Here is the result of this one move:
This looks better already. But wait, there is more - trick #2: Select the background layer (in this case the Spotlight Background layer) and set its layer blend mode to Multiply. Now there is even more hair:
I hope these two simple tricks will make you look like a masking guru!