In multiple exposure, the fusion of several images into a single shot with prolonged exposure over time is a necessary, prevailing condition.
In particular to be able to produce the effects of artificial light, you have to combine several Polarizing filters, ND, GND Cokin so that with a long exposure time and a practically closed diaphragm, it allows you to capture images slowly and progressively.
The same happens in the case of a photograph with continuous exposure, where the interpolation between light and shadow space, carefully reproduces an event.
Once the process has started, it will be necessary to wait for the analog or digital capture to end
Protographer by Gianpaolo Rende