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Lighting a classroom with paper lanterns


Rick Gates

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I'm charged with lighting a small classroom (30' x 20') for a film shoot next month.  We are content with it being brightly lit from above since we're trying to make it look institutional.

We've already determined that the cheap LED tubes in the ceiling will flicker and cause a slow vertical strobe across the image, so they will be turned off.  But because the white, drop ceiling is so high (18'), the first thing that occurred to me is to mount 12 or so paper lanterns in the ceiling to get a bright, even light.

We tested 300W incandescent bulbs, but the we're still not getting the intensity we want.

Is anybody aware of any brighter, screw-in (e26) LED bulbs that would work?  I tried larger, consumer, corn-cob bulbs but flicker and CRI are issues.

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Consumer LED's are hit and miss when it comes to banding. Some are more intense, others less noticeable. And if you use different manufacturers, you'll see banding on banding. Yeah, on Sony cameras at least, consumer LED tints green.

My suggestion would be to use brighter tungsten. Mogul base screw sockets are like 5 bucks, and they allow for 500w and more to run through them. I used Mogul with 1000w tube bulbs in studio. There are also 500w versions. Some may say it's a fire hazard, but that is practically a non-issue suspended in the lantern. It's a halogen bulb incased in a second thicker glass shell that runs cooler. It can still "toast" the paper if resting on the surface over an hours period. A great thing about lanterns is they can be lowered easily. A drawback is power distro, which you can't pull from the house. It'll have to come from generator, renting a few Honda 7000s would work.

An alternative is to use punchy HMI and bounce it overhead. If using the natural ceiling, I'd go for a couple 4ks. Which would amount to 2 Honda 7000s again. You can bring the ceiling closer by suspending a 12x12 or 12x20 ultrabounce frame overhead and using smaller HMI fixtures like 1200s, or 1600s. I'm no rigger, so I'd consult a rigger or gaffer on that solution.

Large spaces with high light gets to a certain expense no matter how you try to do it. The only workaround to the power draw is to use a camera with higher sensitivity. Sony's FX6 has an incredible high ISO of 12000.

Those are my thoughts on that scenario.

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I think I'll take your advice and bounce something bright off the ceiling.  I have a 600D and 2 300Ds.  I'll try putting them next to camera and bounce them off the ceiling to light the wides. I'm a little concerned about the far wall when I do this; it's painted white and might pickup some shine from the bounce.

If I run into that problem, I might attach a 12x12, silk only, to the drop ceiling and bounce it off that. 

Anyway, if this doesn't work it might be time to rent a genny and bring in something bigger.  It'll be my first time renting lights.

Thanks for giving me a direction to follow!

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3 hours ago, Stephen Sanchez said:

Large spaces with high light gets to a certain expense no matter how you try to do it. The only workaround to the power draw is to use a camera with higher sensitivity. Sony's FX6 has an incredible high ISO of 12000.

Not necessarily. One of the biggest challenges in situations like this is getting light into the eyes of your talent. If you don't, your talent's eye will look dark and bruised because a very toppy bounce won't dig into their eyes.

As an alternative, you may want to consider the approach we took on a short film called "Act Your Age" that takes place in a senior center (use this link to see production stills.)  We hung 4'-4 Bank kinos with Opal coved below the fixture to make a "Bay Light." Coving the Opal under the light, redirects it so that it will dig into the talent’s eyes. And you can skirt the fixtures to keep the light off the white walls (something you won’t be able to easily do with a bounce source.) You may also want to consider using a combination of hard and soft light as we did here to create contrast in a situation where the practical lighting is usually very flat.

For a hard light source we powered a 4k Fresnel off the wall. Most schools have a 240V receptacle of some kind. Common 240V circuits in schools include, Copier receptacles, range receptacles, and special receptacles installed for air conditioners. The latest generation of 2.5/4k HMI ballasts will operate on either 120V or 208-240V and fit comfortably in these circuits. If you are using an older ballast that runs only on 120V, you can step-down a 240V circuit to 120V with a transformer. A step-down transformer will convert the 240 volts supplied by 240V receptacles to 120 volts in a single circuit that is the sum of the two single-phase legs of 30/50 amps each (60A usually). Now that you have a larger 120V circuit, you can operate larger lights like 2.5 or even 4k HMIs, or more smaller lights, than you could otherwise.   A step-down transformer can do the same with the enhanced 7500W/240V output of a Honda EU7000is Generator. By giving you access to more "house power" through common 240V household outlets, a Transformer/Distro can eliminate the need for dangerous tie-ins or expensive tow generators (use this link for details.)

As you can see from the production stills, with the right rigging equipment, you can use drop ceilings like a studio grid. Use this link for more pictures of productions that used drop ceilings on location as if they were a studio grid.

Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental & Sales in Boston

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If 240v house lines are available, then the more power to you! That'd be awesome.

Rick, a silk is going to return less light than a solid white surface because it's a porous weave. In addition, I'd be concerned that 1200w of LED will not return a decent light level with an 18ft ceiling or a silk bounce. Consider that can always take light away, but you can't add light if you're fixtures are maxed out. I'll typically run with larger fixtures if I'm put into a situation I'm unsure of.

Eye lights is a great point as Guy mentioned. Anything at eye level will show in the eye. But I'd avoid a hard source for the sake of casting shadows on the background.

@Guy Holt Your first link directs to an index and I couldn't find the short you mentioned. I did find a dumpster scene with two women and three flatheads, it looked like.

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http://www.screenlightandgrip.com/html/slg_home.html

 

You have to click on the link, then look on the left side of the page, scroll down to Portable Grid System.

then on THAT page look on the left side " As NOT seen on TV" and scroll down to
 

Click for more info
about this
and other productions
using the 
Porta-Grid System


 

Edited by Ed Conley
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