FORUMS: list search recent posts

Green Screen light, I'm over whelmed.

COW Forums : Lighting Design

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Drew Jensen
Green Screen light, I'm over whelmed.
on Apr 22, 2010 at 9:23:29 pm

I've searched the forums and have found tons of information, but the problem is, it's all out of my price range. The green screen I'm lighting in only 10x16 foam core. Most people recommend Kino Flo and Videssence. My problem is, I've got to get my lighting both foreground and background at around 1,800 ~ 2K max. Currently we're all Lowel. 2 750W Tota's and 2 44 Rita's. It's come down the chain to try and make the lighting better because we're making some more mobile units. So I was wondering if there are some better ideas on lighting. I've learned a lot on the forums but like I said, most of it is far beyond our budget. Would it be beneficial getting some diffusers for the the Lowel Tota's or some reflective umbrella's? Also, does it even worth adding some green gels for the background to get more of the neon green? I've been at the forums reading the last few days and I feel like my head is about to explode. Are there any good books to get a firm foundation with lighting in general? I've found myself as the "go-to" guy for any information or recommendation, from lights, camera, etc. to post production (software,compression settings, etc.) revolving around our mobile green screen units and I'm feeling swamped. I know this post is a tad long and scattered, but I don't know where else to turn because you guys have been shown to be very helpful and caring.


Return to posts index

cowcowcowcow
Mark Suszko
Re: Green Screen light, I'm over whelmed.
on Apr 22, 2010 at 9:52:43 pm

In my opinion, gelling green screens with green gels is not going to be worth the hassles of adjusting so that the green light is washing evenly, and the gels, if sufficiently dense to make saturated color, will cut down the power of your lights and actually make it HARDER to flood them out and not make hot spots... Some folks here like to do it but to me I'm already trying to match plain light to get even exposure on an already-green wall; mixing in another shade of green to me is just complicating the job.

Green screens do not have to be lit up like a Times Square display in order to work: they just need to be even, well-saturated, and somewhere between 60 and 80 IRE units on the scope, or a stop lower than your talent, and you should be in business. It may be that you're pushing for too bright a screen instead of a dimmer but more EVEN screen.

Speaking to the "evenness" issue, I personally would not use the umbrellas on the Totas, (transmissively they attenuate too much and reflectively they don't work as well or as controllably as a Rifa or Chimera) but instead would use diffusion frames with tough rolux, or a larger, independently supported piece of diffusion, held a foot or so in front of the tota, or a hard silver bounce card.

You could also buy or fabricate a speed ring and wire rods type deal for the totas and make your own softlights like a Chimera or fake Rifa. I make them sometimes out of white foamcore with some tough spun or tough rolux diffusion on the front, clamped to the barn door assembly in such a way that they don't overheat. Stole the idea from Bill Holshevnikoff years ago and it does work, if you follow the directions closely.

I light my green screens with Rifas exclusively, partly, because I happen to have enough of them, and also because they make a great even and flat light. But that's not the only way.

You could change gears and build inexpensive banks of tube fluorescent lights to wash the green screen and keep your electric bill lower, then use the Lowels exclusively for lighting the talent. The color balance difference issue of flo vs. tungsten may not even be an issue then, since the flos have a natural green spike in their spectrum anyway and they are not hitting the talent but only the green screen.

These are my own opinions, and the more experienced gaffers and DP's here might have other suggestions.


Return to posts index

Drew Jensen
Re: Green Screen light, I'm over whelmed.
on Apr 23, 2010 at 2:44:23 pm

Hmm.. you've definitely given me some more things to think through. I've got some questions of what you've said, pardon my ignorance but when you say "between 60 and 80 IRE units on the scope, or a stop lower than your talent". What kind of scope can I use without costing an arm or a leg? Also I'm assuming you mean F-Stop correct? How would I achieve that differentiation between the background and talent? As you can tell I'm very new to this and have kind have been thrown into this blindly.

Also, I've taken a further look at Kino Flo's and for a 10x16 screen could I be ok getting a system like the Kino Flo Single System Two Light Fluorescent Kit (http://www.bhphotovideo.com/c/product/434631-REG/Kino_Flo_KIT_140X_Single_System_Two_Light.html#specifications)? What confuses me is how much light do I need? I see these 4 bank systems and I guess I have not idea how much I actually need?


Return to posts index


cowcowcowcow
Richard Crowley
Re: Green Screen light, I'm over whelmed.
on Apr 23, 2010 at 3:16:33 pm

I light my green screen with $20 "shop lights" from Home Depot. The big green spike in your ordinary fluorescent tubes makes them horrible for shooting regular video. But the green spike makes them ideal for lighting green screen. Be sure to get the kind with electronic ballasts so you don't have the audible hum and the visible strobing from the old-fashioned magnetic ballasts. If you want even color temperature and CRI out of them, you can just put genuine Kino (or equivalent) tubes in the fixtures.

It wasn't clear whether you are talking about a fixed installation or some mobile solution? I put "baby" (5/8 inch) pins on the backs of regular 4-foot fluorescent fixtures so that I can use ordinary grip heads and hold them in place on regular century stands. For a fixed installation, you could just suspend them on light chain (as is the normal method of hanging fluorescent fixtures).

Then, of course, you would use your existing conventional lighting equipment for lighting your foreground actors/props, etc.


Return to posts index

Drew Jensen
Re: Green Screen light, I'm over whelmed.
on Apr 23, 2010 at 4:25:11 pm

Yes it's going to be mobile, sorry for not making that clear. We ship UPS/Fedex and in a crate wherever the shoot location is. I'd really like to get the Kino's but again, I'm not sure how much lighting is enough with their products. I've emailed a sales associate for my region so hopefully I'll be able to get an idea from them. I really do appreciate any and all feedback and input from you guys.


Return to posts index

cowcowcowcowcow
Mark Suszko
Re: Green Screen light, I'm over whelmed.
on Apr 23, 2010 at 5:56:49 pm

If this is going to be shipped around, there is something to be said for using banks of common consumer fluorescent tubes in a standard size: when someone mishandles the shipment and breaks the tubes, you can generally find fast, cheap, emergency replacements on location or within a mile of the location at any office, hardware, Pharmacy or home center type store, but not so much with Kino or Videssence tubes. Thinking even more thrifty, ship the fixtures only, (lighter) and have the guy at the other end bring his own tubes bought locally.

As far as scopes, they are expensive, but worth it. If however you just can't swing it, there are software packages that turn your laptop into a a portable waveform and vector scope. Adobe On Location is probably the most famous one, and that's not all it does, but there are others out there for mac and windows laptops. I'm hoping they come up with one for the ipad, that would be cool.

Meanwhile, you can use the zebra bars in your camera as a poor man's scope. In the zebra bars controls menus of the camera, set it up for say 70 IRE units, then point a wide shot at the green screen and slowly rack the iris opening up and down manually. What you are looking for is for the entire field of view to have the zebra bars come up evenly all around. If one spot starts to show the zebras before the rest, that's your hot spot. If one area has no zebra bars showing, that's a dark spot. Even out the lighting until the zebras are perfect all the way around. Then set the zebra bars to indicate 95 IRE units and start lighting your talent, making sure that only the smallest and brightest little highlights on him or her barely trip that zebra bar overlay. Remember that with digital video, a blown-out white spot on a scene has lost all picture data and that cannot be fixed in post. Slightly under-exposed is much safer and easier to fix later.

Now you should be good to go.


Return to posts index


Drew Jensen
Re: Green Screen light, I'm over whelmed.
on Apr 23, 2010 at 6:44:13 pm

Hey Mark, amazing information. One last question I guess. As far as getting some flo's, would you use them or use Tota's with some diffuser frame? As far as shipping goes, I really don't know how fragile flo's are, but we use military grade cases and pack tightly. But if you think flo's are going to be a problem shipping, then I'll probably steer clear.


Return to posts index

Alan Lloyd
Re: Green Screen light, I'm over whelmed.
on Apr 23, 2010 at 9:30:27 pm

You'll still likely get tube breakage.

I'd also consider using Tough White Silk, a directional diffusion that spreads the beam out and makes even lighting of the green screen easier. Get some and try it - individual sheets are the same cost as other diffusion materials.


Return to posts index

Mark Suszko
Re: Green Screen light, I'm over whelmed.
on Apr 23, 2010 at 11:06:10 pm

What I would choose may not suit your needs, I don't have a budget for new gear so if it was my problem, I would first try working with what I already had. And in that case, I would probably bash together some soft boxes for the totas, out of old studio junk laying around (I'm a terrible pack-rat but it has served me well at times), and cheap parts from Ace Hardware. But would I want to ship that rig and trust other people I don't know, to use it in the field under deadline pressure? My own studio is a benign and safe environment; the field is less so.

So, my advice for you is, if you can find consumer grade flos that will fit your budget and your travel cases, and that adequately light your size of screen, use that cooler-running soft light source to wash your small green screen, then deploy your Lowel lighting gear to light the talent separately. The flos will draw much less power and make less heat, always good in small, badly ventilated spaces.

If I could, I would try to trade your Totas for Lowel Omnis, which are more flexible for many situations. Meanwhile, run the numbers, to see if Chimera-type speed rings with rods and soft fabric soft light envelopes applied to the Totas you already own would cost less than say, four 2-tube flos on two stands.

The Totas push a lot of light out, but it is harsh and not easy to control. One of the things you could try on the Totas is the add-on barn doors, and a Tota-frame gel holder, which fits into a little keyhole slot on theTota's body, same place the umbrella goes: load the holder with diffusion, then use metal binder clips to make a one-foot "frame" around the perimeter of the gel holder using black foil. (If you don't own a roll of black cinefoil, you NEED to.) This is now a quasi-Rifa, hopefully without too much unwanted spill, and you can try washing the screen with two of these, plus your other Rifas.

If you choose to make flos, read up on Walter Graff's "Graff-Lights" to see how he modifies these consumer lights and how they pack down very small and light. You'll need to somehow attach a mounting stud or clip to these lights. I might remove the metal reflector from the consumer flos and replace it with a corrugated plastic or foam core panel set, (backed with foil tape used for heating ductwork) that could fold up small and reduce travel weight.

A golfers' hard travel case, designed for golf bags and clubs, has often been used to protect tripods in shipping; it may hold a couple of these lights and their stands, you'd have to measure everything first to see. The snowboarders also use a hard case for travel, called a "Sports Tube", that may work. Sporting goods carrying cases also sometimes qualify for discounted air shipping rates, look into that.



Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]