Fairytale Scene - The Photoshop: Professional Retouching and Compositing Tips, Tricks, and Techniques - page 459

Figure 9.59
Note
Saving the selection of the children means we will easily be able to remove any of
the lighting effects (which we'll be adding later) that spill over onto them.
2. Click the children group, and Shift-click the Room group at the bottom of the layer
stack. Then go to Layer > Smart Objects > Convert to Smart Object, double-click
the layer name in the Layers panel, and name the layer night ( Figure 9.60 ) .