Eleminate a solid color

quadfmxer_145 · #1 (**permalink**) 08-04-2006, 09:14 PM

If I wanted to eleminate a solid color say a person was standing in front of a wall painted a solid color how would I do that? So the background would be transparent and you could overlap the person onto any background or clip you had. Could you explain a little in depth so I could understand I would appreciate it. I was thinking I would use the chroma keyer. Thanks

RiW · #2 (**permalink**) 08-05-2006, 09:20 AM

I think you are talking about blue/green-screening (or as you correctly said, Chroma Keying.)

This is where you film a person on a solid colour background and then remove the colour so you can put them into any video clip.

First, stand a person in front of a solid colour background - e.g. a wall as you said - but try to avoid shadows and textures as these will not always key out. Film your actors moves and then capture into Vegas.

Then add the video to the timeline and click add a Sony Chroma Keyer Event FX - however, you normally do (e.g. drag-drop it from the Effects tab, right click and then Event FX etc.)
Click the eye-dropper tool and select the colour of your background from the preview window. This should remove the background leaving your person intact (but dont have the person wear clothes that are the same or similar colour to the background) You can then alter the high and low threashold bars to tweak the effect so you can most accurately get rid of the background without the person.

Then add the second video (your new background video clip) to a lower track than the first, and the person will appear in that (in the preview windows) as if he was filmed there in the first place.

~Hope this makes sense

Mark W · #3 (**permalink**) 08-05-2006, 05:19 PM

Also -

Good lighting is the trick. You need to get a good flat light on the b ground and have your talent forward of these lights so they dont cast shadows on the key. Hot, fiddly and space hungry for anything as big as a whole person.

I use a proper chroma b ground, 8 foot sq roughly and 500w builders lights. Torsos is about the best I can routinely manage.

Also dont rely on the colour picker in the chroma plug in too much, results can often be improved by fiddling with the clour sliders.

Vegas claims to be able to sample a clour range by using a box with the colour picker but I havent found this gives any improvemnt over pick a spot and slider fiddling.

Its worth the work cos a good key can look well cool.

Here is a pic of me as a newsreader http://www.zaskarfilms.com/images/ATV/atvpic2.jpg

Many who have seen this film have asked me how i filmed in the news room !

Slrman · #4 (**permalink**) 08-05-2006, 05:25 PM

Damn you! Why can't you ever read any GOOD news! I'm tired of all the doom and gloom.

Mark W · #5 (**permalink**) 08-05-2006, 05:30 PM

Ha, well the film was actually crap but i enjoyed the news reader gag and it looked cool so I might have another go at a news gag sometime.

vegasarian · #6 (**permalink**) 08-05-2006, 06:31 PM

...and remember to throw lots of tungsten backlight onto your subject to decrease colour spillage from your chroma screen

quadfmxer_145 · #7 (**permalink**) 08-05-2006, 06:53 PM

Thanks guys you guys are good. It worked!

Mark W · #8 (**permalink**) 08-05-2006, 08:15 PM

Originally Posted by vegasarian

...and remember to throw lots of tungsten backlight onto your subject to decrease colour spillage from your chroma screen

Ah, thanks for that. No more green fringes from me.

RiW · #9 (**permalink**) 08-07-2006, 08:10 PM

Loved the vid Mark. Where did you get the news room background, or did you make it yourself.

Mark W · #10 (**permalink**) 08-08-2006, 10:48 PM

Originally Posted by RiW

Loved the vid Mark. Where did you get the news room background, or did you make it yourself.

Just a pic off google, bluured and faded a bit in vegas. The screen was also a pic twisted to give depth and the body ouline another pic. I was very pleased with the effect.

I tht the film was far too long but had some good bits, has since been drastically cut and is better for it, might post in user vids soon. ta.