roXor media

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Bluescreen madness

Well, I took some test footage at our dojo the other day with my sensei, Chuck. We hung a huge blue tarp across one wall and then filmed us doing some generally stupid stuff. I took it home, captured it and went to work with Premiere Pro 1.5.

I tried everything under the sun to get that blue tarp out from behind the action. I tried blue screen keying, chroma keying, and difference keying. Notta. Nothing. Zilch. I couldn’t get the tarp out without taking out my pants, too. Ya gotta have pants for cryin’ out loud!

So, what did I learn? Well, for one, you need a ton of light. Like, the damn sun shining on your set at about 10 paces away. Secondly, don’t use a tarp. It’s made of plastic and the camera appears to pick up some of the subtle colors reflected from the person standing in front of it. Hence, no pants.

My best guess is we need to use cloth, and it should probably be green (hell I don’t know, it works for the big time movie makers.) I’ll report in after I can afford that much cloth for some testing. For now, enjoy the horrible fx in this movie I made using what footage I had: Jump Test


Written by Sterling

May 10, 2005 at 3:49 pm

Posted in uncategorized

2 Responses

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  1. Sterling,

    Several thoughts on blue screen

    Plastic works but it should have a matte finish. Plastic table cloth from a party store works well.

    Combine a chroma key and a difference matte. The chroma key can be fairly course and will get most of the solid shapes, while the difference matte will take care of fine hair, motion blur, and translucency.

    Good old fashion sun light is the best lighting. A continous bank of Flourecents at the top edge of your screen and about a foot away renders decent lighting. I haven’t tried it, but a bank aim up off the floor as well probably wouldn’t hurt.

    I haven’t tried this, but it’s something that should help create a better consistence in the screen. Set up your camera so it has a very short depth of field. Focusing on the actor will make the screen blurry evening out some of the discrepancies.

    One issue with green screens is that if you don’t have higher end video equipment or good lighting you can run into some problems with flesh tones having similar luma values.



    May 13, 2005 at 9:21 pm

  2. Mike, thanks for the input. It sounds like you’ve already looked into this little hurdle. I’m going to copy your comments over to the boards if you don’t mind. Thanks again!


    May 16, 2005 at 9:35 am

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