A continuous light such as a torch or candle can be mixed with flash light to create a composite negative with two exposures.
How to get this effect:
1. Set the camera to multiple exposure.
2. Use the camera on a tripod with a cable release.
3. Meter for the flash light (or overhead/daylight in the case of the Picasso or Dance Hall images) and make the 1st exposure.
4. Then in a darkened space where the torch is the only light source use a long exposure to record the movement of the torch (this could be about 20 seconds for example).
5. The torch light will register much better on a dark background than a white one.