Author Topic: How to hang, focus, and strike basic lighting instruments  (Read 13341 times)

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PSMKay

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Hanging
There are two main types of electrics rigging you will encounter: C-Clamp and Unistrut (also known as channel pipe).  C-Clamp, while more versatile, is also not quite as secure.  Unistrut takes a bit longer to get used to and is more expensive to maintain, but makes for a quicker hang once you jump the learning curve and secures the instruments in a much stronger fashion.  Unistrut can also be mounted flush against the ceiling, and so it is often found in spaces with low clearance overhead.

(One of our readers had this to say about Unistrut:)

Quote
Hanging lights on unistrut is rarely, if ever, more secure than hanging lights with a c-clamp. Also, unistrut is a channel, not a pipe, and is NEVER called channel pipe. unless you want an electrician to look at you and say "huh?" Also, a better definition of the rigging would be pipe clamps, which covers a broad category including c-clamps, versus Unistrut, versus floor or wall or other types of mounting...
Plus, it is far easier, and therefore safer to install a safety cable on pipe.

Using C-Clamps:
  • You will need a wrench, preferably attached to your pants by a long-ish piece of tieline if you are climbing.  You will also need a ladder, and it helps to have nice, sturdy work boots. 
  • Using the light plot or the hang tapes, head for the site where the instrument is to be hung.  Depending on the designer, the amount of precision required in placing an instrument varies widely.
  • Loosen the bolt that runs diagonally through the C-Clamp so that the clamp will fit over the pipe.
  • Hook the clamp onto the pipe, making sure that the instrument will be right side up when it is aimed in the direction of the stage.  Finger tighten the bolt until it meets the pipe.
  • If there is a safety cable, clamp it around the pipe and through the yoke of the instrument.  (The yoke is the metal arc that connects the clamp to the instrument itself.)
  • Take your wrench and tighten the bolt as much as you can.  (NB: speaking as a female electrician to male electricians--don't over tighten the bolt, as you never know who's gonna have to take it down.)
  • If you are hanging an ellipsoidal or any similar instrument that has moving pieces that may obstruct the beam of the lamp, make sure to pull them all out as far as they can go.
Using Unistrut:
  • Unistrut pipes are recognizable by their rectangular shape and the approximately one-inch wide channel that runs down the center of them.  Lights are hung on this kind of pipe using a small, specialized nut attached to the yoke that replaces the c-clamp.  The nut is rectangular with sides that stick out from the shaft of the bolt, and it should have two thin grooves running along the side that is towards the instrument.  Many have a spring coming out of the top.
  • See steps 1 and 2 above.
  • Loosen the nut just enough so that it is still attached to the bolt.
  • Push the nut into the channel in the pipe so that the spring presses against the top of the pipe inside.
  • Reach in and twist the nut a quarter turn (NB: most turn more smoothly one way than the other) so that the grooves on the underside of the nut fit over the edges of the channel.   This is often not as easy as it sounds.
  • Finger tighten the bolt from underneath the yoke.  You may have to push up on the yoke while you do this, as the weight of the instrument on the bolt head often creates too much friction to allow the bolt to turn smoothly.
  • Connect the safety cable to the pipe if there is one.  If the pipe is flush up against the ceiling, this may not be possible.
  • Tighten the bolt the rest of the way using your wrench.
  • Pull out all shutters, open all irises, and clear any other moving parts out of the way of the instrument.
Focusing
Focusing determines the direction and shape of the light that is cast on the performance area.  Different types of instruments have different ways to focus them.   Focusing is done as part of the initial light hang, and should be double-checked when you replace lamps.


Focusing Ellipsoidals:
  • Bring gloves and your wrench, preferably attached to your pants with a long piece of tieline.  Wear light clothing--focusing is hot work.  Also bring up with you the color for the instrument in a color frame.
  • Turn on the instrument to be focused.  Check with whoever cabled and patched the plot to find out how to do this.
  • First, make sure all shutters and irises are pulled out/opened as far as they can go.   
  • Loosen the bolt that runs through the top of the yoke.  This bolt connects to either the c-clamp or the unistrut nut.  (Electricians often call this the "Oh sh*t" bolt, as that's what you say when it comes loose and the instrument falls down into the house.)  This will allow you to swivel the instrument from right to left.   If you cannot loosen this bolt, another option on c-clamp systems that will give you the same results is to loosen the tiny bolt that is found on top of the yoke.   (Continuing our lesson in electrician-speak, this is often called the "f*ck me" bolt, as this is what is said when the tiny thing breaks off under the wrench as it is wont to do.)  Don't loosen both bolts, or you'll have nothing but a wobbly instrument.  One will serve the purpose.
  • Now loosen the "banana bolt", which connects the yoke to the instrument itself.  This can get quite hot, so be sure to be wearing your gloves.  This bolt will allow you to move the instrument up and down.
  • See-saw the instrument about until the beam is focused on its target.  In an ideal setting, you will have someone standing on stage so you can aim the hotspot (brightest part) of the beam at them.
  • Once you've aimed correctly, tighten any bolts you loosened in steps 4 and 5.   (This is called locking down.)
  • The designer may ask you to "run the barrel."  In this case, find the bolt on the top of the instrument's snoot, and loosen it.  (This bolt is usually coated in plastic so it can be loosened by hand.)  This allows you to slide the lens apparatus back and forth within the instrument, thereby making the circle of light more crisp or fuzzy as necessary.  Retighten the snoot bolt once the designer is happy.
  • Now, bring in your shutters to fence the light off of any unwanted areas.  Due to the nature of lenses and reflectors, shutters control the opposite in the light beam from where they are actually located on the instrument.  Therefore, to cut light from the top of the beam, you would move in the bottom shutter.  Wacky.
    • If you are working with an ETC brand Source 4 instrument, you will also be able to turn the barrel 45 degrees if the shutters aren't closing off light to the designer's satisfaction.
  • Insert any patterns (gobos) into the pattern slot on top, and add an iris if required.
  • Drop the color frame with color into the guides at the front of the instrument.   Make sure the frame opens upwards, so the color doesn't fall out.
    • Low Budget Alternative: Gaff tape works well for short time periods if you don't have color frames.
    • Other lighting toys to drop in the color guides include top hats (look like coffee cans) and barn doors (which is what the little icon has in the menu bar to the left.)
  • Make sure you turn off the instrument when you're done. 
Focusing Fresnels:
  • Follow steps 1-7 above.
  • Loosen the wing nut on the bottom of the instrument.  This allows you to slide the lamp back and forth within the casing, allowing you to control the size of the beam.   Make your designer happy, and then retighten the wing nut.
  • Follow steps 11-12 above.
Focusing Par cans and Beam projectors:
  • Follow steps 1-7 from focusing ellipsoidals, above.
  • Point and shoot.  There's nothing more you can do.
  • Follow steps 11-12 from focusing ellipsoidals, above.

nick_tochelli

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Re: How to hang, focus, and strike basic lighting instruments
« Reply #1 on: Feb 16, 2012, 09:12 am »
So ever so randomly I was trying to find a method of hanging some fresnels directly into sheet rock at work this morning and I cam across this basic "How to Hang Lights" article.....
......and by golly look who got referenced as a resource at the bottom of the article!! It made me feel warm and fuzzy!
« Last Edit: Aug 01, 2013, 06:37 pm by PSMKay »

Ladytatooine

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Re: How to hang, focus, and strike basic lighting instruments
« Reply #2 on: Aug 01, 2013, 01:54 pm »
Thank you, PSMKay for the information. This helped very much!!!

Deuteronomy75

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Re: How to hang, focus, and strike basic lighting instruments
« Reply #3 on: Aug 02, 2013, 09:06 am »
Focusing Fresnels:
  • Follow steps 1-7 above.
  • Loosen the wing nut on the bottom of the instrument.  This allows you to slide the lamp back and forth within the casing, allowing you to control the size of the beam.   Make your designer happy, and then retighten the wing nut.
  • Follow steps 11-12 above.

Small hints:
1. At some Fresnels, the slider gets stuck when not moved over a long period of time. In this case, switch of the lamp, let it cool down, loose the nut and move the slider several times to both ends until it runs freely. Traditional light bulbs do not like beeing moved aprubtly when lit. (I have my own experience...)
2. Focussing Elipsoidal:
Sometimes, it is better to first set the shutters while the light beam is focused perfectly (borders of the shutters can be seen perfectly) and then "run the barell".

Just 2 Cent from a lighting guy working in Europe.

PSMKay

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Re: How to hang, focus, and strike basic lighting instruments
« Reply #4 on: Aug 02, 2013, 04:06 pm »
Thanks for reviving this. I should note that this is one of the first pieces I wrote for the site, so it's about 13 years old now.

loebtmc

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Re: How to hang, focus, and strike basic lighting instruments
« Reply #5 on: Aug 02, 2013, 04:35 pm »
thank you for fixing the link!

Tags: electrics tutorials 
 

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