Green and Blue Key at the same time- can it be done? at DVinfo.net

Bill Doyle · May 19th, 2007, 04:29 AM

I'm interested in creating a prop that would have both green and blue painted sections so that differnt video sources can be keyed in. I don't do much keying and have never seen this so wanted to know if it's possible.

Richard Andrewski · May 19th, 2007, 05:09 AM

I think this is possible with two passes. 1 pass for keying in the blue source and then run that resulting composite video through a second pass in the same software for keying into the green source. This final result should have the two composites in it. I don't see why this wouldn't work. The other thing to realize is that if the prop isn't locked down (and your camera too), the key will look really cheezy. You may have already realized that though.

Djee Smit · May 19th, 2007, 06:32 PM

I believe Rodriguez did this on sin city, even using 3 colors, also the orange/red kinda color. For instance the background green and orange glasses to create that effect on the glasses of the Elijah Wood character, next to all the other fx

Richard Andrewski · May 19th, 2007, 06:56 PM

Yes I thought about that too. No reason red wouldn't work as long as it's not in any of the other foreground subjects or elements. Then you get 3 passes.

Bill Davis · May 19th, 2007, 07:41 PM

Sometimes the more you overthink these things, the harder you make it on yourself.

There's no law that say you have to fill a single keyed object with a single background plate.

With virtually all of today's NLE software execlling at garbage matts - why not just key on one color and pull various matts to isolate the scenes you want to key to different content?

A modern NLE has virtually unlimted layers. Add that to unlimited matts and there's no reason you can't take a pair of green glasses and file one lens with one source and the other lens with another source.

Add motion paths, and you can key anything into anything, even if it's moving.

Offhand, I can't think of a reason I'd need separate KEY COLORS to do what is being discussed.

Richard Andrewski · May 19th, 2007, 09:33 PM

Because he said he's inexperienced. He probably doesn't know about keyframing and motion paths yet. Those are a bit advanced subjects for someone new to keying. You still have to do two passes even with garbage mattes/rotoscoping too.

Charles Hurley · May 28th, 2007, 11:39 PM

Bill listen to Bill. 2 different chroma keys is silly, 3 is pure comedy. Seriously, a red, blue, and green screen????? What part of the image do you plan on keeping? Once you've created the matte you can do whatever you want. More screen colors will only make it harder to pull a key. Once you've actually done some greenscreen work you'll realize why more screens=more problems. Keep It Simple Sir. Good Luck, Charles.

Jarrod Whaley · May 29th, 2007, 12:30 AM

For this particular application, I'd think the best option would be to use masks with slightly blended edges and not have to worry about keying at all. Depending on the shot, you might be able to save yourself a whole heck of a lot of headache this way. You wouldn't have to evenly light the prop at all, nor would you need to spend any time painting the prop. There might be a little extra time in post (or maybe not, depending on your skill/experience levels at masking and keying), but unless you're paying someone mucho dinero to do your post for you, post time is likely going to be cheaper than production time.

May 19th, 2007, 04:29 AM	#1
Bill Doyle Regular Crew Join Date: Sep 2006 Location: Worcester, MA Posts: 40	Green and Blue Key at the same time- can it be done? I'm interested in creating a prop that would have both green and blue painted sections so that differnt video sources can be keyed in. I don't do much keying and have never seen this so wanted to know if it's possible.

May 19th, 2007, 05:09 AM	#2
Richard Andrewski Major Player Join Date: Jun 2006 Location: Shenzhen, China Posts: 781	I think this is possible with two passes. 1 pass for keying in the blue source and then run that resulting composite video through a second pass in the same software for keying into the green source. This final result should have the two composites in it. I don't see why this wouldn't work. The other thing to realize is that if the prop isn't locked down (and your camera too), the key will look really cheezy. You may have already realized that though. __________________ Richard Andrewski - Cool Lights USA - RED #114 http://www.coollights.biz

May 19th, 2007, 06:32 PM	#3
Djee Smit Regular Crew Join Date: May 2005 Location: Breda, Netherlands Posts: 141	I believe Rodriguez did this on sin city, even using 3 colors, also the orange/red kinda color. For instance the background green and orange glasses to create that effect on the glasses of the Elijah Wood character, next to all the other fx __________________ www.wanah.nl

May 19th, 2007, 06:56 PM	#4
Richard Andrewski Major Player Join Date: Jun 2006 Location: Shenzhen, China Posts: 781	Yes I thought about that too. No reason red wouldn't work as long as it's not in any of the other foreground subjects or elements. Then you get 3 passes. __________________ Richard Andrewski - Cool Lights USA - RED #114 http://www.coollights.biz

May 19th, 2007, 09:33 PM	#6
Richard Andrewski Major Player Join Date: Jun 2006 Location: Shenzhen, China Posts: 781	Because he said he's inexperienced. He probably doesn't know about keyframing and motion paths yet. Those are a bit advanced subjects for someone new to keying. You still have to do two passes even with garbage mattes/rotoscoping too. __________________ Richard Andrewski - Cool Lights USA - RED #114 http://www.coollights.biz

May 19th, 2007, 07:41 PM	#5
Bill Davis Trustee Join Date: Jan 2004 Location: Scottsdale, AZ 85260 Posts: 1,538	Sometimes the more you overthink these things, the harder you make it on yourself. There's no law that say you have to fill a single keyed object with a single background plate. With virtually all of today's NLE software execlling at garbage matts - why not just key on one color and pull various matts to isolate the scenes you want to key to different content? A modern NLE has virtually unlimted layers. Add that to unlimited matts and there's no reason you can't take a pair of green glasses and file one lens with one source and the other lens with another source. Add motion paths, and you can key anything into anything, even if it's moving. Offhand, I can't think of a reason I'd need separate KEY COLORS to do what is being discussed.

May 28th, 2007, 11:39 PM	#7
Charles Hurley Regular Crew Join Date: Feb 2007 Location: Brooklyn NY Posts: 128	Bill listen to Bill. 2 different chroma keys is silly, 3 is pure comedy. Seriously, a red, blue, and green screen????? What part of the image do you plan on keeping? Once you've created the matte you can do whatever you want. More screen colors will only make it harder to pull a key. Once you've actually done some greenscreen work you'll realize why more screens=more problems. Keep It Simple Sir. Good Luck, Charles.

May 29th, 2007, 12:30 AM	#8
Jarrod Whaley Major Player Join Date: Jun 2006 Location: chattanooga, tn Posts: 721	For this particular application, I'd think the best option would be to use masks with slightly blended edges and not have to worry about keying at all. Depending on the shot, you might be able to save yourself a whole heck of a lot of headache this way. You wouldn't have to evenly light the prop at all, nor would you need to spend any time painting the prop. There might be a little extra time in post (or maybe not, depending on your skill/experience levels at masking and keying), but unless you're paying someone mucho dinero to do your post for you, post time is likely going to be cheaper than production time. __________________ -->jarrod whaley. www.oakstreetfilms.com