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GreenScreen Lighting

Discussion in 'Multimedia, Projection, and Show Control' started by PadawanGeek, Dec 26, 2007.

  1. PadawanGeek

    PadawanGeek Active Member

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    Hey Guys,

    I got a 8' x 9.5' greenscreen for christmas, so I need to know the best way to light it on a low budget.

    Thanks and merry Christmas (there are still 12 days, right?)!
     
  2. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    I wondered when/if this would come up, once I saw you got that for Christmas, but no mention of lighting. Here's what I've been told works, though I haven't seen it myself. Buy inexpensive 4' dual tube florescent fixtures with "flicker free" ballasts, two top and two bottom, to light your green cyc. Buy the best 5600K tubes (8+1 spare) you can afford. Light your subject(s) with 5600K light (incandescent corrected with Apollo Full CTB #AP2000 is fine, remember you'll lose intensity), but don't spill onto the cyc. Using 3200K on the subject and 5600K on the drop will be hideous. Be sure to set your video camera to 5600K also, of course. Try to duplicate the lighting on your subject to match the lighting in the, eventual, background. Done wrong, this can make "green screen" output look horrible-a dead give-away. Hope this helps.
     
  3. PadawanGeek

    PadawanGeek Active Member

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    Thanks Derek,

    A couple things:

    The greenscreen is in my bedroom :shock:, so there is 7in non green space on the left side, 0 in on the right side, and 2.5 ft between the top of the greenscreen and my bedroom ceiling. Keep in mind that the screen extends about 2.5 feet out from the wall onto the floor so that we can stand on it. What your saying doesn't really sound like it would work for that. I would like to have something celling mounted so that it doesn't TOTALLY turn my room into a video studio. :mrgreen:

    Thanks and merry Christmas!
     
  4. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Duh, yes, I forgot about the screen extending onto the floor. Perhaps mount only two floro fixtures for the top and Try to keep your frontlights, typically Fresnels, off the backdrop as much as possible so talent doesn't throw shadows on to it.

    Hopefully you'll get some better ideas from some of the vidiots who lurk here. *cough*kwotipka*cough*:)
     
  5. jonhirsh

    jonhirsh Active Member

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    The key to good green screen lighting is separation.

    With out separation of the subject from the green screen you're kinda lost.

    To achieve this you not only need to light the subject and the green screen you need to put a kicker (back light) on the shoulders and head of the subject to give them some dimension.

    With out this back light on the subject you will have a hard time making your animations look realistic and not flat.

    The evenness with witch you light the green screen are key as well. I would suggest borrowing some cyc units or maybe some fresnels.

    JH
     
  6. PadawanGeek

    PadawanGeek Active Member

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    So where can I get those fixtures, im kindof a noob so I dont know what those are :(
     
  7. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Are you near a Lowe's? Here's an 8' dual tube fixture for $33, and two pack of tubes for $9.98, so that seems reasonable. The tubes are 4100K, so you'd use 1/4 or 1/8 CTB on your 3200K incandescent lights, but your camera may like that better anyway. I've been told, but cannot verify, that 8' tubes last longer than 4' tubes.

    The "industry standard" for professional film/video fluorescent applications is a company called Kino Flo, check them out for more information on lighting blue/green screen. Very expensive!

    Or call your favorite local TV Weatherperson and ask him/her for a tour of the set. Once there, see how they do it!
     
  8. PadawanGeek

    PadawanGeek Active Member

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    Thanks! I'm gonna see if someone will take me to lowe's now....
     
  9. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Wait!Stop!Before spending any money, get a second opinion. Don't trust me-- as I said, I've only heard about this second hand. Also, the mounting of any lighting equipment to your bedroom ceiling requires adult supervision. And ALL theatrical lighting fixtures say "Not for Domestic Use."
     
  10. PadawanGeek

    PadawanGeek Active Member

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    AHH!!

    Ok, it's gonna be a while before I get the fixtures up anyway (have to get my dad to go up into attic and give some power and a new switch on my wall.
     
  11. SHARYNF

    SHARYNF Well-Known Member

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  12. cvanp

    cvanp Active Member

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    Most chromakey software can compensate for uneven green screen lighting (though having the lighting even is a huge bonus... makes it easier for you in the compositing stage) but the bigger issue is eliminating shadow. Shadow is a pain to remove and it obviously makes your setup look unprofessional.

    I only lit a green screen once a few years ago so I'm not a good authority on the actual tools to use, but I think the recommendations up to this point are really good.
     
  13. drawstuf99

    drawstuf99 Active Member

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    Yeah, ditto about the separation thing. That is so key. I used to do a lot of video and that's something that takes some work. Watch the distance your talent is to the screen itself, that'll help.

    Also, a lot depends on the camera you'll be using, the software...etc. Generally, though, when lighting it, try to get the least amount of light that produces any hint of green light away from the talent, obviously. Everyone seems to be on the right track, though.
     
  14. kwotipka

    kwotipka Active Member

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    Hopefully you'll get some better ideas from some of the vidiots who lurk here. *cough*kwotipka*cough*:)[/QUOTE]

    Sorry folks, have my head in a Flash project as well as a couple of other things. (Anyone here know Flash Video).

    There are several online guides to green screen work. There are different schools of thought from an asthetic point of view and an equal number from a technical point of view.

    The first thing is that your bedroom is not a tv studio! Well, unless... Anyhow. You don't want a bunch of broken flour tubes all over the place. Now derekleffew has the right idea is that you can use 4' tubes on the cheap. If you go that route, get some 4' clear bulb covers for them. When you break one, it will "help" to contain the mess. Again, you don't want this stuff all over your room! Maybe placing them vertical on either side is safer then top and bottom. Don't get greedy. Just because you have all of that space doesn't mean that you have to use it (or light it). Learn what a garbage matte is.

    We use kino's or soft tungsten lights to light keywalls. Basically, you want the color temps to match but you are lighting two different zones. Light from the key wall should never touch the subject and vice versa. The keywall light should be even and flat and no more then a stop difference between your keywall and subject. Take a white card and hold it against the key wall. Adjust your iris so that the overexposure zebra bars in your camera just come on. Take the card and place it under your key light. Do the zebras come on? Do you have to adjust the iris a lot to get to that point? A light meter here really helps.

    I could ramble on for days but there are other online sources that give you pictures as well. If you have specific questions, send them on. That's what we are here for.

    kw


    PS. Steam out any wrinkles you have in the fabric. These will haunt you in post.
     
  15. wadeace

    wadeace Member

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    some fluorescents will work, but you need to make sure that you keep all the lights the same color temperature. you also need to make sure that you light the screen and the subject separate. any shadows on the screen will cause a bad key, which will cause dark areas and pixeletion and the ever painful halo.

    a relay inexpensive light system would be standard socket light scoops from home depot. than head over to your local photo supply shop to pick up bulbs. the people there should be able to help you there. you will need at least 4 to cover everything.
    go to Woven Shadows: Digital Photography Video Tutorials they are a podcast about lighting and photography. they have lots of great of advice.
     
  16. Serendipity

    Serendipity Active Member Premium Member

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    I'm assuming this has already been solved, but if not, drop me a PM and I'll check with the film & television vidiots at school, as I know they use green screen.

    Also on the topic of green screen lighting, I was comped in to a performance at UCSC where they used a white screen, and back lit it with green gel.
    At first it seemed primitive, but the ability to use the screen for other purposes besides green screening seemed helpful. (Here's some shots of it I found on flickr: 2008-02-28_0045 on Flickr - Photo [email protected]@[email protected]@http://farm4.static.flickr.com/3050/[email protected]@[email protected]@[email protected]@[email protected]@899182467e, 2008-02-28_0089 on Flickr - Photo Sharing!, 2008-02-28_0097 on Flickr - Photo Sharing!)
     
  17. wadeace

    wadeace Member

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    Actually that’s not primitive, it ingenious. Because this method will really help with preventing shadows, which as I said above is key for your key (ha ha, bad pun), although I don’t think they make chroma key green gel, but with digital systems it doesn’t matter too much.

    this being said there are a couple of companies that are making special green screens that are made out of special reflective glass strands, the kit comes with a light ring that goes around the lenses of the camera. This system produces an image that produces an awesome key.
    Reflecmedia: Changing the art of chroma key
     
  18. stevefox

    stevefox Member

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    Here's a link that may be helpful: Chicago Webcam | Chicago Live Cameras | Chicago Weather

    There you can see the lighting setup on the chroma wall at WFLD-TV in Chicago. There are also a few links to other stations, but none of them show the chroma wall that well.

    As you can see, they use two lights in front to light the talent, two more higher up and two lighting from behind to light their key.
     

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