Lighting Effects - The Photoshop: Professional Retouching and Compositing Tips, Tricks, and Techniques - page 165

Figure 3.3
Of course you can always do something extra to take the effect to another level,
and that's what we're going to do here by adding in dust specks, just like you get
around a light source.
To do this I'm going to make use of something I call “thingys.” To create a file like
Figure 3.4 , point your camera to the sky at night and take a photograph of rain, us-
ing on-camera flash.