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Aliasing and Green Screen
So, I wanted make a video where I fight Van Damme, so I downloaded from youtube a video of Jean Claude who execute karate techniques in a green screen, then I made a video of myself where I fight in front of a green screen, well, how you can see from the images, when I started to editing, Van Damme look good, not me, infact I’m full of aliasing, there is something of wrong with my green screen ? It’s cheap but look good.
Try to balance the high and low threshold don’t work, I tried to add some blur, but it’s a poor solution, there is some trick for get rid of aliasing ?
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4 Replies
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[leonardo barone] “there is something of wrong with my green screen ? It’s cheap but look good.”
Sorry, but your green screen does not look good. It’s very poorly lit. You need two sets of lights. One to light the green screen evenly (preferably with soft-boxes), and a second set to light the talent that is separate form the green screen lights. The talent should be a few feet in front of the screen to avoid spill and you should also iron out the wrinkles.
Pulling a good key is all about lighting correctly to begin with. There are plug-ins that you can purchase to make even a bad green screen shot look good (like Boris Continuum Complete Chroma Key Studio) but the Chroma Keyer in Vegas Pro requires a well lit shot in order to work best.
[leonardo barone] “I tried to add some blur, but it’s a poor solution, there is some trick for get rid of aliasing ?”
Actually you were on the right track. Place the Chroma Blur BEFORE the Chroma Keyer and set it to about 1/2 way in each direction. That should clean up the aliasing quite a bit. But the best thing to do is light the green screen evenly and bright.
~jr
http://www.johnrofrano.com
http://www.vasstsoftware.com -
John, thank you for the help, if the problem it’s only the light I will buy lights for sure, do you think these could work ?
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Those will be awesome! Place one soft box on either side of the green screen. If your camera has Zebras, you can use the to make sure that the light is distributed evenly with no hot spots. Then light your talent separately and have them a few feet in front of the green screen and it should be much easier to pull a key.
~jr
http://www.johnrofrano.com
http://www.vasstsoftware.com -
Ok, do you think the problem was only the light or there is more ?
There are some advice for improve more ?
I know for example who is important avoid shadow spot, probably is wise also make sure that the green screen don’t will have wrinkles and folds, maybe iron it before to filming is a good idea.
I don’t know if the thickness of the green screen it’s important.
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