Illuminati Creative Technology, Colchester UK

The content on this page is copyright. Please feel free to use this for any non-commercial purpose, Dorian Kelly reserves the right to be identified as the author of this work

Stage Lighting: A basic manual of the art.

Optical Fibres in the Theatre

Back to home page  

Fibre Optics in the theatre

It is simple really... just put light in at one end of a fibre optic cable and it comes out the other end. Light can go round corners, however much you twist the cable up. Why? Because  a fibre optic is a  thin strand of optical glass inside a thin tube of another kind of optical glass. If you put some light into the core, it bounces around and cannot escape until it gets to the far end because it reflects off the tube by which it is surrounded.

It’s brag time…
Illuminati was one of the pioneers in the use of optical fibres in the theatre, purchasing lengths from Rank Optic for experimentation when they were the only UK producers, and using them for props and practicals and early fairly crude starcloths.
We were not the first to use them on any scale in a musical – that privilege went to theatre projects who made a  large animated backclothon using panels of masonite with holes in it, lots of harnesses and CCT silhouettes with colour wheels, a project which was featured in “Tabs” or was it “Cue”?


Theatrical grade glass  or plastic fibre optics: how to make some: 

Take a thick cylinder about a meter long of optical quality glass ( or polymer)  and coat it with a different kind of glass (or polymer)  with different optical properties. Then heat it  up and let it flow through a set of dies and sensors until it is a few microns thick and several miles long. Or better still, get someone ( like Par Opti or Universal Fibre Optics ) who has the equipment do it.

Then make bundles of say, 150 or more of these and coat each whole bundle in black or clear plastic. Its now known as a “tail” or “cable”. Take as many of these tails as you need, cut them  to desired length (anywhere  up to about 10 metres long or as short as you like) and  bundle them all together  with tape or  heat shrink tubing at one end. This is now called a “Harness”

At each of the free ends, carefully strip the plastic for a few millimetres, dip in into resin, and crimp it into a thin brass tube. At the common end, strip each tail back a  couple of centimetres and resin bond all the individual raw fibres together. Then carefully cut the end into a flat face and polish it dead flat with finer and finer grades of abrasive, finishing with talc, and eventually paper. Insert the whole lot into a piece of brass or other metal tubing and it is ready to go. The finished common end assembly is known as a 'ferrule' Offer the ferrule up to  a light source  and the light will appear like stars at the far end.

The light source can be virtually any suitable lamp: at the lower end of the scale, a 20 watt dicroic reflector lamp can be used or at the other end a high intensity discharge lamp. or anything in between. There might optionally be a flicker wheel or a colour wheel inserted between the lamp and the harness. The optical properties of the lamp used should be selected to cover the fibre bundle fairly evenly: this not only avoids hot spots and uneven bightnesses, but should also prevent heat from being concentrated in one place. The heat of the lamp can damage the fibres,especially plastic ones, so be careful to use a heat shield if necessary.

Fibres may be End Glow: As much light as possible comes out of the end of the fibre, and as little as possible is allowed to escape through the sides.  

Or they can be Side Glow or Edge Glow: This is done by scientifically damaging the outer jacket of the fibres to allow some of the light to escape. Sometimes the actual fibres are wrapped around a highly reflective interior core to help light output .

Photo and fibre by Par Opti



The light sources can sit on a flown bar and each of the tails can be poked through the cloth and secured with a one of the proprietory clips that various companies make, or even a blob of hot melt glue. A flicker wheel giving a very slow and gentle change looks good. Here is a picture of one of our Starcloth designs, "ILLUMINATI AURORA" based on an ancient Japanese screen pattern

Starcloth I
Back of fireworks cloth

Animated Fireworks:

This is dealt with at length elsewhere on this site.


Props and practicals

A fibre optic satellite prior to it being installed in a theme park interactive shooting gallery in France.

Pirate fuse Here’s  a picture of an animatronic pirate about to light the cannon with a fibre optic fuse. You can also make brilliant non-portable candles, chandeliers and candelabras
fibre fountain This fountain was formed from raw fibre encased in UV active clear resin and animated to give a sparkling running water effect. A terrible picture of a beautiful effect.


back to illuminati homepage
Back to tech index page