The answer is, it’s easy, and needs only one dimmer channel. Plus a couple of hours work in the shed. The technique described doesn’t appear to be published in any of the standard stage lighting works, but has been used for many years, the “secret” having been handed from lighting tech to lighting tech.

I was shown this trick by a chap called Brian Beckley, who was a very accomplished stage director for an amateur theatrical association of associations called NATHDA (‘The Norbury and Thornton Heath Drama Association’), on a little lighting course he once ran. Mind you, that must have been over a decade (or two) ago. However the trick works as well in the 90′s as it did then. Thank you Brian.

A word about Shop Safety

This project uses mains voltages, which are hazardous, and can cause death. Your insurance company may not like you building this project, nor may they like you using one of these in a show. Your theatre may even object to you using DIY effects in their venue. Ensure that you (and your show) have appropriate cover for your activities and liabilities.

And be sure to read our disclaimer.

Overview

The flickering effect is generated by simply

using a low wattage coloured bulb in series with a fluorescent tube starter. The starter does it’s thing, and tries to start the ‘tube’, but of course, it never can. So your bulb just keeps flickering in (and this is what makes the effect look good) a random and unpredicatable way.

Of course, real fires have more than a single flame, so grouping together a number of these flickering lights (I like to use three) and using different coloured bulbs (I like to use opaque red, clear red, and amber) makes the effect more realistic.

The only other thing to say is that the effect works best if you have your dimmer set at 50-60%; like many good lights this one looses it if you turn the wick all the way up.

Thats all there is to it!

110V(USA) versus 230V(Rest of world)

Although this trick works well in both 110V and 230V countries, the type of starter needs to be varied, due to the different avalanche voltages. Sadly, I’ve lost track of the citizen of the USA who pointed this out to me, some considerable time ago.