Lighting Effects - The Photoshop: Professional Retouching and Compositing Tips, Tricks, and Techniques - page 176

Figure 3.12 Lighting effects are added to the paintings and lamp.
Tip
If you want to add more light sources, simply duplicate the light 2 group by hold-
ing down Command/Ctrl+J. You can then reposition that duplicated group using
the Move tool, resize it using Free Transform, and control the brightness with the
Opacity slider.
Gradient Lighting: Part 1
This technique creates a lighting effect that goes through a transition, either from one color
to another or fading to transparent.
It's a great technique for mimicking the look of street lighting, because it goes from warm
(nearest the light source) to cool (farther away), as in Figure 3.13 .
Figure 3.13
This gradient lighting effect has been used to add warm street light coming in from the
right; it becomes cooler toward the lower left, as it would do in reality.