Green screen without lighting?

Discussion in 'Fan Productions' started by Matthew Raymond, Feb 22, 2019.

  1. Matthew Raymond

    Matthew Raymond Fleet Captain Fleet Captain

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    Oct 24, 2016
    I've been lazy. Should have finished this months ago, but I got distracted by work an other pet projects. I have the gesso, the cardboard and the sandpaper, but I need to order more of the retroreflective paint, and I might need more primer. I recently used up a lot of primer painting DIY storage tubes for a couple of shotgun microphones. I think I'll order three cans, one white, one grey and one black.
     
  2. Tom Servo

    Tom Servo Commodore Commodore

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    New York, New York
    When I was in school for VFX, we had a system that works exactly as this does. Reflectmedia screen, with an LED ring that would project green light that you could mount around the camera lens. It worked quite well, but you had to make sure you were really squaring up the camera to the screen to get the bouncy correctly. It was nice because you didnt really get much spill on the subject since the green leds were just bright enough to get a bounce off of the reflectmedia screen.
     
  3. Matthew Raymond

    Matthew Raymond Fleet Captain Fleet Captain

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    Oct 24, 2016
    I've ordered a teleprompter to see if that can be used in place of a light ring. I'm also going to experiment with using it for a form of front projection, since it works under similar principles.
     
  4. Matthew Raymond

    Matthew Raymond Fleet Captain Fleet Captain

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    Oct 24, 2016
    Just finished the cardboard prototypes. I took two pictures, both with the original large prototype in the background for reference.
    [​IMG]
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    This pretty much came out as I predicted. White and black got brighter by basically the same amount, so I don't really think the color matters that much, although I think grey might work better for general keying because it's likely to be closer to the brightness of the keying light. Black came out pretty well, I think, and I do think it could be useful for windows out into space as I said before. White might be useful for both the keying light and ambient light, but I suspect you'd just want to light the subject separately from the keying surface anyways. Strange thing about white was that there was a slight yellowing when the retroreflective paint was applied.

    I've ordered an RGB ring light to see what this looks like with the normal lights on and a green keying light. My initial results with the teleprompter didn't yield much, as the reflected iPad was too dim to be seen properly. I'll keep trying, though. I might try putting a projector under it instead of just an iPad, but I'm concerned there will be too much of a green wash and that too much light will reflect off the hood.

    Generally, I'm going to rule out using gesso and cardboard. The gesso easily warps the cardboard as much as spray paint alone, so while you save paint, you add gesso without preserving the shape of the cardboard. Also, it's not as easy as I thought it would be to sand the surface of the gesso smooth. Honestly, I'm getting the impression that it may be easier to simply clip retroreflective cloth to a wooden or PVC frame. Or perhaps use cardboard as a structure to hang the cloth on. Just don't try to paint it.

    Another option is to put something like contact paper on the cardboard and spray paint that. Hmm... Not sure I have the energy to try that at the moment. Making the previous prototypes was a lot of work. Three coats of gesso, each sanded, two coats of primer, each lightly sanded, and two coats of the retroreflective paint. With drying time, it basically takes a week to make these things.
     
  5. publiusr

    publiusr Vice Admiral Admiral

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    publiusr
    The milky look might help tell a ghost story.

    One of the things to try might be to have a green screen floor, and the camera hung from the ceiling pointing downwards. Now, roll a disk station model with a flat edge to roll across the floor, and drop the camera on its stalk.

    You have a rotating saucer that you zoomed in on—and the effects are all in-camera pretty much.

    Water tanks may work.

    Imagine a base with your paint, and you gradually increase the light to have it materialize. Tower shaped spacecraft are seated in sockets glued with some explosive s shock detach the craft in what appears as a lift-off. Use the paint on the base, and green screen behind the tank.

    Have the base filled upside down, so the bubbles flow along it, if you separate heavy towers to have them sink. With the camera also upside down, you have another lift-off look.

    Volcanos in a water tank can have fuller’s Earth or lycopodium such that the plumes look like pyroclastic flows.

    I’ve noticed that when weather men forget and wear green, you can still see some outlines. These can be called lines of force for a story. Powder versions of the paint might be thrust.

    In Adult Swim’s OFF THE AIR, I have seen...dissolves I guess, where the background image breaks into new shapes.

    A green painted ghillie suit could intensify this effect, as a monster...
     
  6. Matthew Raymond

    Matthew Raymond Fleet Captain Fleet Captain

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    Oct 24, 2016
    How do you focus the camera? How to you keep the saucer from wobbling? Seems easier to paint a wall instead of the floor and use a turn table for the saucer with a painted blind to hide the mechanism, and just dolly the camera passed the saucer.
    I've messed with a green suit, but the effect isn't perfect because any harsh light will cast shadows on the suit that ruin the matte:
    https://drive.google.com/file/d/1gKC5LpHb-wnrVH7SsD9Wel58P2CjSmEJ/view?usp=sharing
    Of course, that's not really practical with retroreflective paint. Just the movement of the person in the suit will brush off the little beads that reflect the light.
     
  7. Maurice

    Maurice Fact Trekker Premium Member

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    Oct 17, 2005
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    One ferry ride from Starfleet HQ
  8. Matthew Raymond

    Matthew Raymond Fleet Captain Fleet Captain

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    Oct 24, 2016
    The RGB ring light arrived. If everyone would like to see pictures, I can take some and post them, but long-story-short, the retroreflective paint appears to be too weak to be useful. The green of the ring light, under normal lighting conditions, simply doesn't show up well enough on anything but prototype with the black primer, and even then it's too dim for keying purposes.This is probably the reason why my experimentation with the teleprompter didn't fair so well. The paint simply wasn't reflective enough for the dim light of the teleprompter to be visible. I think I'll save up and order a few yards of retroreflective fabric and try again with that.
    That might have worked, but the real problem was that the dragon in the video was a greenish-blue that was too close to the green keying color, which made it harder to key. I should have either chosen my subject's color based on the opponent color of my keying color or vice versa. That said, using a green pole to move the dragon would have probably worked better.
     
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