Screening out white backgrounds

jeremyhung · Sep 7, 2009

hey guys,
i was wondering how u can screen out (if that's what its called) white backgrounds.
i got some cool footage from detonation films that im planning to use, but they come with white backgrounds.

simply keying out the color didn't work as well as i thought it wouldve.
any thoughts?

thanks.

countevil · Sep 7, 2009

Keying out the colour is what you'd do.
If you have Song Vegas for example, take either the green or blue keyer and apply it. Then simply change the keying colour to white.

I won't look perfect at first, you have to mess around with the levels and maybe adjust the contrast.

Filming Guy91 · Sep 8, 2009

I've used that stock footage from detonation films as well, with Sony Vegas Movie Studio 8. The chroma key effect worked just fine, though it didn't look too professional. However, achieving that effect would take quality compositing and effects software, so that's to be expected.

Stardust Walking · Sep 8, 2009

Use a mat or mask generator, not chroma key.

Terry

Telemendo · Sep 9, 2009

Sometimes I have found a Luminance key to work better than chroma for white backgrounds.

knightly · Sep 9, 2009

Screen = black is transparent
Multiply = white is transparent

or is it the other way? can never remember, but overlay is 50% gray is transparent.

jeremyhung · Sep 17, 2009

Thanks knightly! I think that's it!

visualfxpro · Sep 24, 2009

Luma is the way to go!

That is the way to do it. This is exactly what the luminance key is for. However you must consider two factors:

chromatic resolution (4:1:1...4:2:2); highly compressed formats will be a pain even with good software
Software: You really should be using something like After Effects for this. Good luck with an editor and lelss than perfect footage.

Telemendo said:
Sometimes I have found a Luminance key to work better than chroma for white backgrounds.