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Old May 9th, 2008, 07:59 AM   #1
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Green Screen on a budget

Hi folks,

This is a continuation of a thread in another section of these boards but is more light specific.
I've just read through several pages on here (and other sites) discussing worklights as a cheap option for setting up a light rig.
I have to get this set up over the weekend so I can present tests (at least) of green screen footage.
After just about managing to self build a green screen (from conduit/accessories and a sheet of green cotton) I now have to pay attention to lighting this.
Having had a look through local hardware stores I can see a couple of cheap options:

*500w halogens on tripod (perhaps not as high as one would like) - would 1 as a fill suffice?

*150w halogens (w/o tripods) - I thought perhaps these lower rated lights could be used to light the green screen (which I'm led to believe you shouldn't light too much?)

*halogens clamps

*flourescent worklights - approximate to 250w.

I may have scanned through one or two posts too quickly but might it be possible to replace the halogen bulbs with CFL bulbs...or does it take a few more adjustments than simply that?

For diffusing I thought of creating a frame with muslin/cotton sheeting stapled to it (either a door frame made from light timber or something smaller....I assume anything to close to the halogens at least will smolder in no time!).
I'll be testing in my living room - not sure whether halogens in the ceiling can be used as some kind of back light/rim light or to direct green spill downwards rather than on the subject:

http://farm3.static.flickr.com/2237/...372b41.jpg?v=0

Then of course there's the possibility of creating barn doors from card (I like the pre made barn doors posted on here but I need to be set up by the morning) and afixing gels to the kit (magenta for any back lights should I manage to set any up).

Here's a link to pretty much everything I can obtain from local hardware stores in the uk (I can't see an appropriate scoop solution)


http://www.wickes.co.uk/bin/venda?ex...archsubmit.y=0

Forgive me for my lack of experience on this, hopefully if this jobs comes off I can invest in a more pro set up.

Any advice will be most appreciated...I'll be onto these stores later today/early morning.

Many thanks.
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Old May 9th, 2008, 08:54 AM   #2
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What are you planning that you need softboxes for the size of doorways?

Basically 'on a budget' your only concerns are:
- A background in basically any contrasting color (or even black or white)
- Minimizing (color) spills

Making sure the background is even and evenly lit makes for much better keys. Get it as best you can. Use any lights you think will do the job!
Do not mix color temperatures for lighting the talent.

The goal of the 'greenscreen' is not to get a good key but to get a believable composite. Getting a good, clean key is nice as it saves you time and makes it easier to create a believable scene.

When you can't get the best screen possible, it will just take more time to clean up. Some software keyers can do a better job than others, saving you time.

A smaller FoV is easier to light evenly. If you're building a huge set, you'll have more challenges.

George/
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Old May 9th, 2008, 09:56 AM   #3
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Quote:
Originally Posted by George Kroonder View Post
What are you planning that you need softboxes for the size of doorways?

Basically 'on a budget' your only concerns are:
- A background in basically any contrasting color (or even black or white)
- Minimizing (color) spills

Making sure the background is even and evenly lit makes for much better keys. Get it as best you can. Use any lights you think will do the job!
Do not mix color temperatures for lighting the talent.

The goal of the 'greenscreen' is not to get a good key but to get a believable composite. Getting a good, clean key is nice as it saves you time and makes it easier to create a believable scene.

When you can't get the best screen possible, it will just take more time to clean up. Some software keyers can do a better job than others, saving you time.

A smaller FoV is easier to light evenly. If you're building a huge set, you'll have more challenges.

George/
This will be footage of a subject just talking to the camera. Eventually the background (for these jobs at least) will be white (a la apple adverts...although obviously not with the equipment I'm guessing it takes to make those commercials).
I'm doing a series of tests in my living room at the moment and it it comes off 'ok' then I guess the budget will be increased (via a series of jobs) giving scope for more pro equipment (and no doubt a larger studio space).
This will mostly end up on a web page rather than for a DVD.

My only concern now is the lights (the door frame idea came from the shower curtain on a pole to diffuse light from these halogen 500watters).

At this point I'm hesitating over grabbing one or two 500w tripod haolgens (for key and fill) and a couple of 150w for the screen...back fill I could perhaps use another 150w on a clamp behind the subject.
...then there's the question over could I swap out the 500w bulbs with CFL's which would no doubt be half as bright but a lot cooler and efficient...then of course I get into mixing colour temps and use of gels!
Hope I'm making sense?!?

It's a warm day (we get them occasionally in blighty :) ) and I'm anxious to pick up a set either this evening or on the morrow - the test footage has to be with the client at the beginning of next week.


Cheers.
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Old May 9th, 2008, 11:50 AM   #4
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My favorite budget screen lighting approach involves 2 5-gal buckets, 1 or two sacks of concrete, 2 8' pieces of electrical conduit, 4 u-bolts, and 2 2-bulb 4' shop light fluorescent fixtures with electronic ballasts, lamped with high-cri bulbs, everything from a home-hardware superstore.

Lessee', the concrete is mixed and into the buckets, stick in the conduit and harden. That's the stand. The fixtures get u-bolted onto the conduit. Easy.

Yes, you must have two fixtures for screen light. Even-ness is everything here. The 4' fluorescents are your friend here.

Yes, you must have backlight. It can be extremely difficult to cut the key without it. Magenta is a nice touch on the backlights, but having some distance between the subject and the screen helps more.
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Old May 9th, 2008, 12:04 PM   #5
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Originally Posted by Seth Bloombaum View Post
My favorite budget screen lighting approach involves 2 5-gal buckets, 1 or two sacks of concrete, 2 8' pieces of electrical conduit, 4 u-bolts, and 2 2-bulb 4' shop light fluorescent fixtures with electronic ballasts, lamped with high-cri bulbs, everything from a home-hardware superstore.

Lessee', the concrete is mixed and into the buckets, stick in the conduit and harden. That's the stand. The fixtures get u-bolted onto the conduit. Easy.

Yes, you must have two fixtures for screen light. Even-ness is everything here. The 4' fluorescents are your friend here.

Yes, you must have backlight. It can be extremely difficult to cut the key without it. Magenta is a nice touch on the backlights, but having some distance between the subject and the screen helps more.
I've seen more conduit this week than I'd seen in my whole life!

Do you have a link to the fluorescent lights you are referring to (or should I step out of the 'worklight' jurisdiction and pop over to the kitchen lighting section? Not sure if I've seen those in my local searches - they stock the halogen's to the hilt though.
There's this type:

http://www.wickes.co.uk/invt/187109

giving approx 260w of lights but there 4 times the cost of the halogens...
Given I'm lighting both the subject and the screen and wouldn't really want to mix CRI's and Halogens if possible (colour temp).
I'm popping out in a bit to take a quick look at the options...

Many thanks.
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Old May 9th, 2008, 04:20 PM   #6
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No, what you want is more like this:

http://www.wickes.co.uk/Fluorescent-...ng/invt/162285

Except go for the 4 foot tube T8 model and make sure it has an electronic ballast. Typically in most Home Depot type places they will have some commercial 4 foot ceiling type fixtures. Maybe like ones used in a kitchen or office. Shoplights are fine too. The 2 and 4 bulb ones are what I am thinking of. I've shown this before but one of my customers did a DIY screen setup for less than $2500 USD using these type lights and some Cool Light 6x55 studio flo models for talent lighting where more control might be needed.

http://www.coollights.biz/wordpress/...tegory/gallery

He used the "linoleum" method for making the screen and it looks terrific. Several rows of shoplights overhead and aimed down at 45 degree angle. 4 foot daylight tubes used all over.

Using a cracked ice or prismatic diffusion panel over the fixtures will yield an even smoother lighting on the screen without cutting much light.
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Old May 9th, 2008, 04:45 PM   #7
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When doing greenscreen, absolutely every little thing counts if you want to get a convincing composite. Do a test shot, create a quick composite and give it an honest evaluation. If it doesn't feel right, then something's wrong. And sometimes you'll have to think long and hard to get it right.

Here's a list of things to consider:

Lighting on the screen has to be even, and the purer the green, the better it is for the most part. Simple is better. I've seen some try to fix a badly lit setup by adding lights, only to make things worse. Want to fix a hot spot? Pull the light farther away.

Compositing or keying software makes a huge difference. I have Keylight and Primatte and, of the two, I find Primatte much more adaptable and controllable.

Edges count! Bad edges mean bad keys and are among the biggest giveaways when it comes to composited scenes. Getting good edges requires using formats which have good color info. 4:2:2 is ideal. 4:2:0 works very well in HD. And 4:1:1 has to be the worst possible choice.

Is the lens clean? Does it create any sort of chromatic aberrations? Those aberrations can make it very difficult to control the quality of the edges.

You don't need a backlight if you have good keying software, use the right codec/format and work carefully. In fact, the backlight could spoil the overall effect, especially if there's nothing in the scene to warrant light coming from that direction.

Lighting is extremely important. Where is the light coming from? Hard light? Soft light? Do the shadows make sense compared to the background? Are the highlights right? Any reflections?

As a kid I recall seeing Bonanza and the studio-shots simulating outdoor scenes didn't make sense. There were too many shadows heading in different directions. So be aware that even a 10-year-old can spot a bad composite.

And when you do assemble the composite, you need to match the color of the light hitting your subject to the color of the background. And here's a very important tip that I'm hesitant to give away, only because it took a lot of thinking to get it right: It's not just the color of the light hitting your talent. Take note of the color of the light filling the shadows, too.

Here's something I did recently. Shot with the Sony EX1. I made the mistake of setting a negative value for "crispening" and should have left it at zero.

http://www.hawaiigoesfishing.com/vid...een_sample.mov
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Old May 9th, 2008, 05:21 PM   #8
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David,

You've got a wealth of information here. I'll add my 2 cents...

The fluoro lights Richard suggested I think are your best option for now. Halogen worklights are just too risky and hot in most situations. They'll work, but the fluorescent route will get you further.

That being said though, it's hard to get a good backlight with a fluorescent light so you'll want something with a little punch.

You could very easily use (2) of the 2 bank fluoro shop lights. If you're using any worklights, and you're not color correcting them, I'd suggest using a tungsten balanced fluorescent bulb so your lighting matches. This keeps the green screen from relflecting back the blue of the daylight balanced bulbs. Shoplights with bulbs here are about $20 for the each light plus bulbs. Pretty cheap. Not only that, you can swap out bulbs and keep using them. They're very handy, provide nice soft light for your green screen and run very cool, which is critical in small rooms.

I'd recommend a third bank for your keylight if you want to go that way. Again, very soft, even light. Use a piece of foamcore to bounce your fill into your talent.

Now.. if you're needing to match to a background, say like Dean showed (nice example, Dean!) you may want harder light (match the sun for example) which the fluoros won't give you. If you're going for generic lighting to throw in any background, I'd stick with softer light.

The 150 watt shop light I would use as your kicker / backlight.

Also - get your talent as far away from your background as possible. This prevents spill which your cotton fabric will give you. The magenta gel is good in certain circumstances if you're using a less robust NLE keyer but in most cases any third party keyer will have sufficient spill suppression and I know a number of VFX guys now who have sworn off the magenta / minus green gel solution due to the issues is gives when they're matching background and light wrapping with the software. Even in Sony Vegas, I've got a good spill suppression technique and do not use Magenta gels on my backlight.

What camera are you using? Makes a big difference as well like Dean pointed out. Most cameras, even prosumer cams have a zebra setting in them - turn this on and light according to it. You want about one or two stops from no zebras to full zebras - set at 70 - 75 ire and you'll get a nice bright green to key.

like I said, I'm only trying to add to the pot of goodness here.. lots of great suggestions.

mike
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Old May 9th, 2008, 05:31 PM   #9
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BTW: The setup I used had three lights. Two Lowel Tota Lights on the background (eefx.com green screen fabric) and one 500 watt Tota Light on the talent to simulate hard sunlight. Not flattering lighting at all, but realistic enough.
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Old May 9th, 2008, 06:19 PM   #10
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Thanks, Dean.

That reminds me, David. In Dean's case he used two of his three lights on the background. For interactive lighting, you could light your talent with a candle for what it's worth, but if the background isn't evenly and properly lit, it won't matter how you light your subject.

In Dean's case, he had one key light, up and to the subject's left to match the sunlight direction in the background place. Notice though he got some fill out of it as well, not just the direct sunlight. More akin to actual sunlight and yes, while not flattering, it's very real.

Again, if you light your background separately and correctly, you can do anything you want with your talent.

I'll also second the eefx green screen. Absolute best I've ever used.

mike
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Old May 10th, 2008, 03:51 AM   #11
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Huge thanks to you all for posting this advice.

I perhaps should've posted the link to my original thread in the JVC boards -
However to summarise:

I'm shooting on an extremely tight budget (the mention of $2500 is completely beyond me at this moment!) - this is for a test - if it comes off ok (and I've explained this to the client) there's scope (either through payment for the jobs or the company themselves will buy the kit in) for a more pro set up.

*Shooting 720p25 via the JVC HD100

*Editing/keying in either FCP or Motion 2 (which contains Primatte RT)

*For this project the client will eventually require a white background (although they may of course change their minds - the advice on lighting for a more realistic effect is invaluable - Dean's example is fantastic).
TBH - I've played around with stills in images, cutting out subjects to place on other backgrounds adhering to the concept of the light matching etc.

*I built a frame from plastic conduit and made a 'green screen' from the most natural green cotton material I could find.

*I'm having to shoot this is my living room with the screen facing a window.

Quote:
The fluoro lights Richard suggested I think are your best option for now. Halogen worklights are just too risky and hot in most situations. They'll work, but the fluorescent route will get you further.

That being said though, it's hard to get a good backlight with a fluorescent light so you'll want something with a little punch.

You could very easily use (2) of the 2 bank fluoro shop lights. If you're using any worklights, and you're not color correcting them, I'd suggest using a tungsten balanced fluorescent bulb so your lighting matches. This keeps the green screen from relflecting back the blue of the daylight balanced bulbs. Shoplights with bulbs here are about $20 for the each light plus bulbs. Pretty cheap. Not only that, you can swap out bulbs and keep using them. They're very handy, provide nice soft light for your green screen and run very cool, which is critical in small rooms.

I'd recommend a third bank for your keylight if you want to go that way. Again, very soft, even light. Use a piece of foamcore to bounce your fill into your talent.
With this in mind (and I have to make a choice on these lights by later today latest as the client would like to see footage on Monday!) might I be along the right lines with the following:

Two four foot (twin?) fluorescent shop lights for the background (will I need large gels to balance the daylight/match the tungsten, if I were to use a halogen worklight?)

Excuse my lack of experience but I'm still not sure what I would now use for the fill/key - was originally going to use a 500w halogen but a: I'll be mixing colour temps and b: sounds like these might be overkill?

I appreciate this is the weekend and you guys are quite a few hours behind the uk, but if anyone is around to advise me through the home straight (I feel I'm almost there!!) I'd be hugely grateful.

Cheers.
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Old May 10th, 2008, 04:23 AM   #12
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...just to add:

If I manage to source the 4 foot twin lights (with diffuser and electronic ballasts) - noted also that the majority of these are hardwired (adding to a lighting ring), so is it possible to add a mains plug?? - might this 260w equivalent fluorescent light be good for a key fill or could I light the subject with the aforementioned halogens (bounced/reflected and either the 150w or the 500w).

http://www.wickes.co.uk/invt/187109

Cheers.
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Old May 10th, 2008, 10:45 AM   #13
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David,

In trolling my fav royalty free lib I noticed that Digital Juice had a new (PDF) magazine out. It features a "how did we do it" for the "Tech Know" series, which should be somewhat close to the look you're striving for with the white background.

It may be a good read: http://www.digitaljuice.com/magazine/default.asp

George/
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Old May 10th, 2008, 02:45 PM   #14
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David,

In trolling my fav royalty free lib I noticed that Digital Juice had a new (PDF) magazine out. It features a "how did we do it" for the "Tech Know" series, which should be somewhat close to the look you're striving for with the white background.

It may be a good read: http://www.digitaljuice.com/magazine/default.asp

George/
Hey thanks George - I'll take a gander at that shortly. Cheers for the linkie.

Quick update - I found twin 4 foot fluorescent tubes (hard wired - I'll have to rewire them for mains supply) but the physical store themselves hadn't any in :( I'll have to rush around in the morning (sods law in that all stores in the region are either out of stock or extremely low).

http://www.diy.com/diy/jsp/bq/nav/na...&isSearch=true

seem to be the one's referred to - 4 foot. Although I'd have to fix up some DIY stands for them.

Whilst at another store I found this:

http://www.screwfix.com/prods/49932/...KLIGHT-_-49932

which may come in handy as a fill...possible key...it's pretty bright but nothing like the 500w halogen would give. Still toying with the idea of getting a 150w halogen worklight as a key, but I'll trial this tomorrow morning.
Surprised that having a back light or not having one has split opinions, hopefully when I play with Primatte I'll get away with not having one.
Cheers.
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Old May 10th, 2008, 10:34 PM   #15
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Two four foot (twin?) fluorescent shop lights for the background (will I need large gels to balance the daylight/match the tungsten, if I were to use a halogen worklight?)
Cheers.
Not necessary to gel these to match your subject lighting. Green is green for the most part and daylight color temp is IMHO better for getting a truer green. You'll white balance to the subject / foreground lighting hopefully with the green screen lighting turned off. Then after white balance, turn the screen lighting back on and you're ready to go.
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