Rigging and Focusing Lights: Safe Working Procedure

Owned by Karen Cook (Unlicensed)
Last updated: Jan 15, 2015


Useful terms to know:

Rig. To hang lights in their position on lighting bars or in other specified positions.

Focus. To set the position and beam attributes of the light.

Circuit. As a noun; where the light is plugged in at the bar. As a verb; to plug the light into a circuit.

Patch lead. The male end of the circuit, by the dimmers. Each patch lead corresponds to a circuit, and they share an identifying number. 

Patch. To plug the patch lead into a dimmer.

Dimmer.  The power distribution device for conventional theatre lighting, controlling how much power a light gets and therefore how bright it is. The unit of twelve dimmers is a dimmer rack.

DMX. The electronic communications system which allows the lighting control desk to “talk” to dimmers and intelligent fixtures.

Channel. The identifying number on the lighting control desk, which controls a dimmer and any light patched into it. In a small system like at the Hayman Theatre, the channel and dimmer number are often the same.

Patch sheet. The document recording technical information about each channel, including its dimmer number, circuit number, colour number, and position. 

Vista. The brand name for the lighting console, used to control the lights.

 

Follow this procedure for the safe and correct use of theatre lights.

 

RIGGING

  • Conduct a visual inspection of the light to ensure it is safe to use, and has a current test tag. Check that all the light’s accessories (barndoors/shutters, gel frame, safety chain, hook clamp) are present and secure. 
  • Place the hook clamp fully over the lighting bar, ensuring it is not on top of any cables. Tighten the tri-nut.
  • Secure the safety chain around the bar and yoke/pick-up point.
  • Point the light in the approximate focus and tighten the tilt lock.
  • Fully uncoil the cable and circuit the light (plug it in), ensuring the cable is not resting on the light and there is enough slack to focus. Do not tightly wind the cable around the bar. Use electrical tape to secure the excess if necessary.
  • Ensure the circuit is turned on.
  • Fully open the barndoors or shutters.
  • Fully spot the light. For fresnels and PCs, this means positioning the focus knob towards the back of the light. For profiles, the knobs will be at either end of the lens tube.

 

PATCHING

  • Before patching, ensure the dimmers are switched off.
  • Patch (plug) the cable of each circuit into the appropriate dimmer. If you have more than two lights in a dimmer, make sure they do not exceed the 2400 watt limit. If in doubt, consult the Production Coordinator.
  • Once you have finished patching, turn on the dimmers.
  • Flash out (check) each light using the lighting desk. Do not snap the lights to full – fade them up to a low level. Correct any errors.

 

FOCUSING

  • Fade in each light to full over several seconds.
  • Move the focus knobs slowly and smoothly, to avoid damaging the globe or lenses.
  • Loosen knobs only as much as is needed, and tighten when positioned.
  • The lamp will get hot quickly. Try to only touch the handles or the yoke. Ensure you do not turn on the light earlier than necessary. If the light gets too hot, turn it off and come back when it has cooled, or use gloves.

 

CHANGING GLOBES

  • If the globe blows while the light is being focused, do not attempt to replace the globe immediately. It will be extremely hot. Give it time to cool (could be 30 minutes or more, depending on prior use), or swap out the whole fixture and replace the globe later.
  • Do not touch the glass part of the new globe. Use the cardboard sleeve included in the box to handle the globe. If you touch the globe, clean it immediately with methylated spirits.