EX1 & Green Screen

Dean Sensui · October 1st, 2008, 01:29 PM

Hi Wes....

The lighting is very simple. Just two Lowel Tota lights to illuminate 10-foot-wide EEFX.com green screen. Then a single light to illuminate the talent.

The green screen is exposed at 50 IRE to put it right in the middle of the exposure scale. It maximizes any chroma information and gives the keyer the best chance of getting the most out of the available image data. It also minimizes flare which then helps with keying fine objects. If the green is too bright it starts to bleed into the foreground elements and makes keying more difficult.

Also, you must white balance for the background light. Not the foreground light. That green needs to be exposed and recorded as accurately as possible. While many keyers can compensate for problems, try to alleviate problems at the start so you're not facing issues in post.

Cindy is lit separately. The light is adjusted to get her right where she needs to be on the exposure scale, independently of th background.

The background plate is shot in advance. Then the single Lowel DP light in the studio is adjusted to match the angle and quality of the light in the background plate.

I might make a simple "model" to take into the field that will allow me to quickly record the lighting qualities and make it easier to duplicate the lighting conditions in the studio.

As for outdoor lighting, it's usually early morning or late afternoon.

Hope this helps!

Mike Chandler · October 3rd, 2008, 01:28 PM

Dean: How are you measuring that 50 IRE? And you're saying you balance for the green regardless of the subject lighting?

Charles: Super short. Congrats.

Dean Sensui · October 3rd, 2008, 02:10 PM

Mike...

I use camera zebras to get the 50 IRE. Set the zebras at 50 and make adjustments until the green screen is barely covered in them.

As for white balancing for the green screen illumination: absolutely.

Consider this: It's the computer's ability to sort out what is green and what isn't that make a keyer work. The purer the color, the easier it is for the computer program to sort out the difference between the background and foreground.

By white balancing for the light hitting the green screen you help ensure that you're getting the cleanest primary color possible whether it's green, blue or red.

You could illuminate the green screen with a green light but that's not necessary. Besides, if you're doing a full-body shot then you can't have that green light falling all over the talent.

Some people use in-camera settings to achieve a "look" but sometimes those settings can make it really tough to pull a key. If the look involves desaturating the color, that's a huge problem. In fact anything that skews the cameras response to color can create serious problems in post because the keyer depends entirely upon chroma information to pull a key. Give it bad chroma information and you're going to get a bad key. Better to create that "look" in post after the keying step.

Mike Chandler · October 3rd, 2008, 02:54 PM

Thanks, Dean. But does that still mean you're setting your aperture for subject first? Say I've got a location lighting setup that yields an aperture of 3.4 (and no higher) for best exposure of the subject under tungsten. Do you then remove the subject, fill the screen with the green, and check that your zebra's are blossoming at 50%?

Dean Sensui · October 3rd, 2008, 03:09 PM

Mike...

I'm shooting in a studio.

So I'll set the green screen lighting first, then place the talent. Then the lighting for the talent is set up and adjusted to suit the exposure established by the green screen, and to match the direction and quality of light in the background plate.

Keith Moreau · February 27th, 2009, 01:06 AM

Dean, I've been inspired with your flawless chroma keys you've shown here. I'm also trying to do some keying of people into natural settings.

I'm evaluating Primatte Keyer Pro 4 based on yours and other recommendations within Final Cut Pro 6. I like all the flexibility of the controls, although I'm having some trouble with blond hair on a blue screen, but the main problem I'm having is that it's really slow to render. Like 40 seconds of keyed EX1 footage takes 20 minutes to render. And it's really slow when adjusting Primatte. I'm using a very fast Mac Pro 8 Core with plenty of memory.

Do you have any suggestions? I like it but if it's this slow I probably need to look elsewhere. The Motion Primatte lite is basically instant rendering. Right now it's using only 1 core or sof of processing power, from what I can see.

Are there things I should try to speed it up?

Has anybody tried using Shake 4.1 for chroma keying? Any other recommendations?

Thanks for any advice.

Dean Sensui · February 27th, 2009, 01:32 AM

Keith...

I'm using Primatte from within After Effects, and it's making use of the graphics card as well as the eight processors. So that could account for a considerable speed difference. Other than increasing the number of "instances" in Qmaster I don't really know if anything can be done to help FCP access all eight processors and make full use of the GPU. Maybe that's something which might be found in a future release of FCP?

For keying around hair you might want to key the hair separately from the rest of the talent. I often do that, and a lot of other compositors do the same. Key settings that work for a white blouse, for example, might not be ideal for a wedding veil or smoke.

In Primatte there are some refinement tools. The ones that might be of particular value for hair is "spill plus" and "spill minus". And "matte plus" and "matte minus". These will let you "creep" toward a working setting. Each time you drag the cursor through the problem area, it makes a slight adjustment. Make sure you're using a "point" selector instead of a "rectangular" selector.

Another very powerful tool is "lightwrap". Works great to integrate edges of the foreground into the background, and can even help induce realistic "flare" when a foreground item intersects a bright object in the background. But it usually kills off fine detail when it comes to wispy hair.

So there are lots of tools in Primatte. Just keep in mind that you may need to do multiple keys to solve different problems. Rarely does a single key setting work perfectly for all elements in an entire scene.

Also, the better you get, the more critical you become, and the longer it takes!

Brian Luce · February 27th, 2009, 01:51 AM

I'm impressed by the keying too (I'm also impressed by Cindy!). Speaking of Cindy, what did you use to light her? I don't think you said, only that you used "A single light".

Keith Moreau · February 27th, 2009, 02:27 AM

Hi Dean

Thanks for the info. I don't know how to do multiple keys such as for the hair, but obviously it's possible so I'll figure that out. I have played around with all kinds of settings, including the light wrap, and I like it.

However, the pokiness is getting me down. Even before rendering it's really slow, so it makes trying things out and looking at the preview in the canvas painful. I have a really fast graphics card, an ATI Radeon HD 3870 GPU and Primatte is an FXPlug so it should be using the GPU of the Radeon.

I've heard some complaints about Primatte's speed with FCP. I also just tried using it in Motion and it still seems as slow. I don't have Adobe After effects.

Do you use Final Cut Pro? If you have a moment could you see if Primatte is slow for you there? I don't know if I can afford the $900 bucks right now for After Effects since I use other apps for what After effects can do.

Thanks for the advice and help.

-Keith

Dean Sensui · February 27th, 2009, 02:33 AM

Quote:

Originally Posted by Brian Luce

I'm impressed by the keying too (I'm also impressed by Cindy!). Speaking of Cindy, what did you use to light her? I don't think you said, only that you used "A single light".

Cindy? Hehe. Lots of guys are impressed, too. She used to be a TV news reporter here, was doing news on the radio, and even played a role or two on ABC's "Lost". She's gradually developing a different personna for this type of work. It's not the usual newsy approach. It's more of a conversational style.

I use a Lowel DP light on her. Sometimes I'll use a diffuser, depending on what the background plate looks like. For example, one scene was in Kona where volcanic haze is often a problem. I softened the sunlight just a little to match the types of shadows I was seeing.

We're always half-joking about what she needs to wear for a particular shoot. Recently I told her she was going to be at a reservoir in breezy and chilly Nuuanu valley, so bring a jacket.

Dean Sensui · February 27th, 2009, 03:00 AM

Keith...

Yep, I use FCP for all my editing.

To do multiple keys, you will need to create a different layer for each key. Mask off the area you want to key, then work on that section. It means being able to move the mask if the area you want keyed also moves. Can be very painful in FCP. So if you're doing a lot of keying you might want to consider investing in AE.

FCP is a great editor. But not so good when it comes to doing composites. That's really the realm of AE. BTW, AE is a lousy editor.

I don't know if the version of Primatte I have will work in FCP as it's really intended for After Effects. I'm just guessing but the speed problem might be FCP's inability to work with all the processors on the Intel Mac. I believe Primatte is very processor intensive with all the calculations it has to make on how it differentiates between what's green and what's not. I've noticed that FCP isn't making full use of available resources with ordinary rendering, too. Observing how it works through the Activity Monitor, I don't see all eight columns of the readout maxing out. With AE, all eight columns are maxed out.

Brian Luce · February 27th, 2009, 03:34 AM

Quote:

Originally Posted by Dean Sensui

Cindy? Hehe. Lots of guys are impressed, too. She used to be a TV news reporter here, was doing news on the radio, and even played a role or two on ABC's "Lost". She's gradually developing a different personna for this type of work. It's not the usual newsy approach. It's more of a conversational style.

I can't believe people that look like her work in RADIO. Thanks for the insights though. Keep the faith Dean, must be tough over there in Hawaii, with Cindy, the deep sea fishing, the beaches etc. I feel for you.

Keith Moreau · February 27th, 2009, 11:59 PM

Dean, what version of After Effects are you using? Maybe I can get a good deal on a version earlier than CS4. I could also download a trial I think and see if Primatte works faster with it. Regarding FCP using multiple CPUs I think you are right it should be a little better than it is right now at that.

Dean Sensui · February 28th, 2009, 04:32 AM

Keith...

I'm using CS3. Production version.

Dean Sensui · February 28th, 2009, 04:39 AM

Quote:

Originally Posted by Brian Luce

I can't believe people that look like her work in RADIO. Thanks for the insights though. Keep the faith Dean, must be tough over there in Hawaii, with Cindy, the deep sea fishing, the beaches etc. I feel for you.

Yep, life can be tough... :-)

Seriously, I've been though a couple of trips where the sea was so rough you had to be on all fours to get from the fighting chair to the cabin. Lots of bouts of sea sickness. And a few trips where days were spent in the middle of nowhere with no fish.

It beats canning pineapples.

October 1st, 2008, 01:29 PM	#16
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	Hi Wes.... The lighting is very simple. Just two Lowel Tota lights to illuminate 10-foot-wide EEFX.com green screen. Then a single light to illuminate the talent. The green screen is exposed at 50 IRE to put it right in the middle of the exposure scale. It maximizes any chroma information and gives the keyer the best chance of getting the most out of the available image data. It also minimizes flare which then helps with keying fine objects. If the green is too bright it starts to bleed into the foreground elements and makes keying more difficult. Also, you must white balance for the background light. Not the foreground light. That green needs to be exposed and recorded as accurately as possible. While many keyers can compensate for problems, try to alleviate problems at the start so you're not facing issues in post. Cindy is lit separately. The light is adjusted to get her right where she needs to be on the exposure scale, independently of th background. The background plate is shot in advance. Then the single Lowel DP light in the studio is adjusted to match the angle and quality of the light in the background plate. I might make a simple "model" to take into the field that will allow me to quickly record the lighting qualities and make it easier to duplicate the lighting conditions in the studio. As for outdoor lighting, it's usually early morning or late afternoon. Hope this helps! __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing

October 3rd, 2008, 02:10 PM	#18
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	Mike... I use camera zebras to get the 50 IRE. Set the zebras at 50 and make adjustments until the green screen is barely covered in them. As for white balancing for the green screen illumination: absolutely. Consider this: It's the computer's ability to sort out what is green and what isn't that make a keyer work. The purer the color, the easier it is for the computer program to sort out the difference between the background and foreground. By white balancing for the light hitting the green screen you help ensure that you're getting the cleanest primary color possible whether it's green, blue or red. You could illuminate the green screen with a green light but that's not necessary. Besides, if you're doing a full-body shot then you can't have that green light falling all over the talent. Some people use in-camera settings to achieve a "look" but sometimes those settings can make it really tough to pull a key. If the look involves desaturating the color, that's a huge problem. In fact anything that skews the cameras response to color can create serious problems in post because the keyer depends entirely upon chroma information to pull a key. Give it bad chroma information and you're going to get a bad key. Better to create that "look" in post after the keying step. __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing

October 3rd, 2008, 03:09 PM	#20
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	Mike... I'm shooting in a studio. So I'll set the green screen lighting first, then place the talent. Then the lighting for the talent is set up and adjusted to suit the exposure established by the green screen, and to match the direction and quality of light in the background plate. __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing

February 27th, 2009, 01:32 AM	#22
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	Keith... I'm using Primatte from within After Effects, and it's making use of the graphics card as well as the eight processors. So that could account for a considerable speed difference. Other than increasing the number of "instances" in Qmaster I don't really know if anything can be done to help FCP access all eight processors and make full use of the GPU. Maybe that's something which might be found in a future release of FCP? For keying around hair you might want to key the hair separately from the rest of the talent. I often do that, and a lot of other compositors do the same. Key settings that work for a white blouse, for example, might not be ideal for a wedding veil or smoke. In Primatte there are some refinement tools. The ones that might be of particular value for hair is "spill plus" and "spill minus". And "matte plus" and "matte minus". These will let you "creep" toward a working setting. Each time you drag the cursor through the problem area, it makes a slight adjustment. Make sure you're using a "point" selector instead of a "rectangular" selector. Another very powerful tool is "lightwrap". Works great to integrate edges of the foreground into the background, and can even help induce realistic "flare" when a foreground item intersects a bright object in the background. But it usually kills off fine detail when it comes to wispy hair. So there are lots of tools in Primatte. Just keep in mind that you may need to do multiple keys to solve different problems. Rarely does a single key setting work perfectly for all elements in an entire scene. Also, the better you get, the more critical you become, and the longer it takes! __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing

February 27th, 2009, 03:00 AM	#26
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	Keith... Yep, I use FCP for all my editing. To do multiple keys, you will need to create a different layer for each key. Mask off the area you want to key, then work on that section. It means being able to move the mask if the area you want keyed also moves. Can be very painful in FCP. So if you're doing a lot of keying you might want to consider investing in AE. FCP is a great editor. But not so good when it comes to doing composites. That's really the realm of AE. BTW, AE is a lousy editor. I don't know if the version of Primatte I have will work in FCP as it's really intended for After Effects. I'm just guessing but the speed problem might be FCP's inability to work with all the processors on the Intel Mac. I believe Primatte is very processor intensive with all the calculations it has to make on how it differentiates between what's green and what's not. I've noticed that FCP isn't making full use of available resources with ordinary rendering, too. Observing how it works through the Activity Monitor, I don't see all eight columns of the readout maxing out. With AE, all eight columns are maxed out. __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing

October 3rd, 2008, 01:28 PM	#17
Mike Chandler Major Player Join Date: May 2008 Location: Moab, UT Posts: 264	Dean: How are you measuring that 50 IRE? And you're saying you balance for the green regardless of the subject lighting? Charles: Super short. Congrats.

October 3rd, 2008, 02:54 PM	#19
Mike Chandler Major Player Join Date: May 2008 Location: Moab, UT Posts: 264	Thanks, Dean. But does that still mean you're setting your aperture for subject first? Say I've got a location lighting setup that yields an aperture of 3.4 (and no higher) for best exposure of the subject under tungsten. Do you then remove the subject, fill the screen with the green, and check that your zebra's are blossoming at 50%?

February 27th, 2009, 01:06 AM	#21
Keith Moreau Major Player Join Date: Nov 2006 Location: Brisbane, California Posts: 530	Dean, I've been inspired with your flawless chroma keys you've shown here. I'm also trying to do some keying of people into natural settings. I'm evaluating Primatte Keyer Pro 4 based on yours and other recommendations within Final Cut Pro 6. I like all the flexibility of the controls, although I'm having some trouble with blond hair on a blue screen, but the main problem I'm having is that it's really slow to render. Like 40 seconds of keyed EX1 footage takes 20 minutes to render. And it's really slow when adjusting Primatte. I'm using a very fast Mac Pro 8 Core with plenty of memory. Do you have any suggestions? I like it but if it's this slow I probably need to look elsewhere. The Motion Primatte lite is basically instant rendering. Right now it's using only 1 core or sof of processing power, from what I can see. Are there things I should try to speed it up? Has anybody tried using Shake 4.1 for chroma keying? Any other recommendations? Thanks for any advice.

February 27th, 2009, 01:51 AM	#23
Brian Luce Inner Circle Join Date: Jan 2006 Posts: 2,290	I'm impressed by the keying too (I'm also impressed by Cindy!). Speaking of Cindy, what did you use to light her? I don't think you said, only that you used "A single light".

February 27th, 2009, 02:27 AM	#24
Keith Moreau Major Player Join Date: Nov 2006 Location: Brisbane, California Posts: 530	Hi Dean Thanks for the info. I don't know how to do multiple keys such as for the hair, but obviously it's possible so I'll figure that out. I have played around with all kinds of settings, including the light wrap, and I like it. However, the pokiness is getting me down. Even before rendering it's really slow, so it makes trying things out and looking at the preview in the canvas painful. I have a really fast graphics card, an ATI Radeon HD 3870 GPU and Primatte is an FXPlug so it should be using the GPU of the Radeon. I've heard some complaints about Primatte's speed with FCP. I also just tried using it in Motion and it still seems as slow. I don't have Adobe After effects. Do you use Final Cut Pro? If you have a moment could you see if Primatte is slow for you there? I don't know if I can afford the $900 bucks right now for After Effects since I use other apps for what After effects can do. Thanks for the advice and help. -Keith

February 27th, 2009, 11:59 PM	#28
Keith Moreau Major Player Join Date: Nov 2006 Location: Brisbane, California Posts: 530	Dean, what version of After Effects are you using? Maybe I can get a good deal on a version earlier than CS4. I could also download a trial I think and see if Primatte works faster with it. Regarding FCP using multiple CPUs I think you are right it should be a little better than it is right now at that.

February 28th, 2009, 04:32 AM	#29
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	Keith... I'm using CS3. Production version. __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing