Home Forums How can I do this? Archives Sloppy Key on Virtual Set

This topic contains 2 replies, has 2 voices, and was last updated by  Eric Pratt 2 years, 7 months ago.

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    We just got out Trinity system in and I love it…but have been experiencing a few difficulties as expected. The main one is that I am designing a virtual set to be used in the Trinity (our news has been virtual set for over a year). We have been using a full green screen with an “Ultimatte” system and have had no problem…however now when I try to key through the Trinity no matter what adjustmenst I make, I am getting a pretty sloppy key. Just can’t get rid of the green halo. Any suggestions?


    I’ve found that an Ultimatte system is one of the best at keying. Having said that, you may get better results through your switcher and that system.

    However, the keyer in the Trinity was a major concern for me as well. We now produce a weekly spot using Trinity’s virtual set and have to be very careful to get a nice, clean key. The thing that made a MAJOR difference was when we started going component analog into our BetaSP instead of composite. The composite just wouldn’t key sharp enough for us. Now that we’ve gone component, the keys look pristine.

    The ‘key’, of course, is to have very even lighting on your backdrop and your talent. I recommend soft scoops or highly diffused 3 point lighting. Backlighting is critical to make the talent ‘stand out’ from the set, so make sure you give it the attention it deserves.

    If you have any questions, call me at 318.752.6150

    Hope this helps,

    Anthony D. Coppedge


    Eric Pratt

    The first thing to look at is your signal, component will yield a signal infinitely better than anything else (though I must confess that last week at VideoMaker I was pulling an awfully good signal of an S cable). The second thing to look at is your lighting, 3 point lighting is great, but as long as you have a nice even light on the screen that will do. The third aspect of keying to keep in mind is the actual key settings, for our greenscreens I usually use something like 220,20,20,20 with minor variations for ambient lighting and subject. But start with 0,0,0,0 and run the hue until you’ve knocked out the most color that you can, when you get close click to the left or right of the slider and move the numbers one at a time until you find the perfect hue number. Then run the width up until you’ve knocked out all the color, even the fuzz in the talent’s hair. Now bring up the low sat until their hair and clothes come back and finally adjust the softness to taste. So far I have never had a problem getting a pristine key with that method. Some other things to consider, if you are getting a black line or a green line to either side of the talent then you may need to adjust the Chroma H Delay. If you still can’t get a good key give us a call.

    Eric Pratt
    Trinity Tech Rep


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