Green Screen on a budget

George Kroonder · May 20th, 2008, 06:11 AM

If you have a difuser, like you can have with office lighting fixtures, you could replace them with the "egg crate" basically they're just a grid intended to make the light more directional. In fixtures they're may also be called Louvres (French for "blinds", so technically not the same).

On 'proper' softboxes the egg crates are mounted on the difuser.

You may have to experiment with your setup to get the look you want.

George/

David Scattergood · May 20th, 2008, 07:27 AM

^^ Cheers George - I'll know what to ask for when I ring around now.
Many thanks.

David Scattergood · June 5th, 2008, 08:00 AM

Hey folks - apologies for dragging this back up from the sea-floor, but I have a slight concern over some test footage I shot on green screen last night.
There appears to be a few disagreements over whether you should white balance for the screen or for the subject.
Last night when I shot this footage I initially lit the screen and subject (*although still not entirely to my liking) then once focused I went ahead and filmed. This first shots were without white balance (it looked sharp and bright enough as it was).
The second shots I white balanced on the subjects face ( 4/5 foot from the camera) - this looked far more natural, although the subject now looks either underlit (possible given the weak CRI single key/fill) or under exposed. Also of concern (and bewilderment) is that the white balance shots seems to be softer than the first lot!?!?

*This identifies my lack of experience, although edging ever closer! Unlike previous footage with the green screen I used a back light (500w halogen - bounced off a white ceiling such was it's brightness - might perhaps try a lower 150w lamp next time) on the subject to help 'bring him out' a little. I couldn't get hold of a magenta gel in time and will need to flag off the 4' Flori tubes (my 'mock kino's' - pic attached!) to catch some of the spill.

Cheers.

Pics:
Without white balance: http://i56.photobucket.com/albums/g1...itebalance.jpg

With white balance:
http://i56.photobucket.com/albums/g1...itebalance.jpg

http://i56.photobucket.com/albums/g1...lightstand.jpg

Dan Brockett · June 5th, 2008, 08:22 AM

Quote:

Originally Posted by David Scattergood

Hey folks - apologies for dragging this back up from the sea-floor, but I have a slight concern over some test footage I shot on green screen last night.
There appears to be a few disagreements over whether you should white balance for the screen or for the subject.
Last night when I shot this footage I initially lit the screen and subject (*although still not entirely to my liking) then once focused I went ahead and filmed. This first shots were without white balance (it looked sharp and bright enough as it was).
The second shots I white balanced on the subjects face ( 4/5 foot from the camera) - this looked far more natural, although the subject now looks either underlit (possible given the weak CRI single key/fill) or under exposed. Also of concern (and bewilderment) is that the white balance shots seems to be softer than the first lot!?!?

*This identifies my lack of experience, although edging ever closer! Unlike previous footage with the green screen I used a back light (500w halogen - bounced off a white ceiling such was it's brightness - might perhaps try a lower 150w lamp next time) on the subject to help 'bring him out' a little. I couldn't get hold of a magenta gel in time and will need to flag off the 4' Flori tubes (my 'mock kino's' - pic attached!) to catch some of the spill.

Cheers.

Pics:
Without white balance: http://i56.photobucket.com/albums/g1...itebalance.jpg

With white balance:
http://i56.photobucket.com/albums/g1...itebalance.jpg

http://i56.photobucket.com/albums/g1...lightstand.jpg

Hi David:

I think the white balance on your subject looks better in 2 and 3. You have a lot of wrinkles in your green screen that may make it more difficult to pull a clean key, always try to smooth out the wrinkles using weights and stretching and pulling.

Dan

David Scattergood · June 5th, 2008, 08:48 AM

Thanks Dan - yes the white balance pic was far more natural (without it looked pretty garish - the subject's face is almost orange - although he's naturally darker skinned which presented a new challenge for me - there is a skin parameter on the HD100 but I was too concerned with other things to use that). I'm glad you feel the true white balance works better - I'll just have to brighten up the key/fill next time and brighten this in post.
Should've added - the third pic was just a snap of the makeshift flori (taken with a digi still cam).

I'd attached ringlets to the material and stretched them, but being slightly under pressure last night I forgot to weight them down (I'll matte out the creases in this footage). I'll probably invest in a pro set up (although not that expensive via ebay) should I get a run of jobs from this one.
I was impressed with myself bearing in mind the amount of skills I pulled together here (first real indoor/studio set up outside of my own tests...I kept a cool head on (not so easy under that 500w halogen) and the potential client looked impressed.
Many thanks.

Daniel Epstein · June 5th, 2008, 09:38 AM

In my opinion the wrinkles left on the Jpg are not as much of a concern as the overall lighting of the background. The background should be lit much flatter with as few shadows as possible. Your keyer may be able to deal with this as this is a chroma key not a luminance key but you want to make the background one color and the shadows could get your green out of range of the keyer.

Seth Bloombaum · June 5th, 2008, 10:59 AM

Quote:

Originally Posted by David Scattergood

...There appears to be a few disagreements over whether you should white balance for the screen or for the subject...

There should be no disagreements. The skin tone of the subject rules, always. Chromakey software can deal with varying shades of green, but skin tones gotta' be right.

David Scattergood · June 5th, 2008, 02:25 PM

Quote:

Originally Posted by Seth Bloombaum

There should be no disagreements. The skin tone of the subject rules, always. Chromakey software can deal with varying shades of green, but skin tones gotta' be right.

Cheers...I must remember to reset the zebra (set at 60-70% for green screen first off...such a checklist that has to be drummed into you in this game eh :) )

Thanks seth. Must admit it makes total sense to WB the subject. Saying that, I've had to take a little of the colour down via FCP's 3 way CC - the subjects face was off a little (even after WB it was a little too 'warm').

Quote:

In my opinion the wrinkles left on the Jpg are not as much of a concern as the overall lighting of the background. The background should be lit much flatter with as few shadows as possible. Your keyer may be able to deal with this as this is a chroma key not a luminance key but you want to make the background one color and the shadows could get your green out of range of the keyer.

Daniel - for the area I'm using on the green screen I was ok in this instance. The subject is sat down and is only moving his head and head ever so slightly. The bit I needed was uniform zebra - it's where it gets darker where I'd get unstuck if that space was used. I'll matte the darker area's off but I'm fairly pleased with FCP's chroma keying tools.
I think my problem was with the 2x twin flori lights in as much as they're either too close to the screen (perhaps explaining why the top and sides are shadowy); not bright enough (36w...could try higher watted tubes); the diffuser might do with coming off (and the aforementioned flags/sheilds placing around the units.

I've always shot outdoors (or well lit interiors) rather than studio with video...this is where the 'photon management' comes in...and it isn't altogether easy. However with help from you guys I'm slowly getting there!

Many thanks.

May 20th, 2008, 06:11 AM	#46
George Kroonder Major Player Join Date: Jan 2008 Location: Utrecht, NL \| Europe 3rd Rock from the Sun Posts: 612	If you have a difuser, like you can have with office lighting fixtures, you could replace them with the "egg crate" basically they're just a grid intended to make the light more directional. In fixtures they're may also be called Louvres (French for "blinds", so technically not the same). On 'proper' softboxes the egg crates are mounted on the difuser. You may have to experiment with your setup to get the look you want. George/ Last edited by George Kroonder; May 20th, 2008 at 09:00 AM.

June 5th, 2008, 08:00 AM	#48
David Scattergood Major Player Join Date: Aug 2006 Location: Manchester, UK Posts: 755	White Balance Query Hey folks - apologies for dragging this back up from the sea-floor, but I have a slight concern over some test footage I shot on green screen last night. There appears to be a few disagreements over whether you should white balance for the screen or for the subject. Last night when I shot this footage I initially lit the screen and subject (although still not entirely to my liking) then once focused I went ahead and filmed. This first shots were without white balance (it looked sharp and bright enough as it was). The second shots I white balanced on the subjects face ( 4/5 foot from the camera) - this looked far more natural, although the subject now looks either underlit (possible given the weak CRI single key/fill) or under exposed. Also of concern (and bewilderment) is that the white balance shots seems to be softer than the first lot!?!? This identifies my lack of experience, although edging ever closer! Unlike previous footage with the green screen I used a back light (500w halogen - bounced off a white ceiling such was it's brightness - might perhaps try a lower 150w lamp next time) on the subject to help 'bring him out' a little. I couldn't get hold of a magenta gel in time and will need to flag off the 4' Flori tubes (my 'mock kino's' - pic attached!) to catch some of the spill. Cheers. Pics: Without white balance: http://i56.photobucket.com/albums/g1...itebalance.jpg With white balance: http://i56.photobucket.com/albums/g1...itebalance.jpg http://i56.photobucket.com/albums/g1...lightstand.jpg

May 20th, 2008, 07:27 AM	#47
David Scattergood Major Player Join Date: Aug 2006 Location: Manchester, UK Posts: 755	^^ Cheers George - I'll know what to ask for when I ring around now. Many thanks.

June 5th, 2008, 08:48 AM	#50
David Scattergood Major Player Join Date: Aug 2006 Location: Manchester, UK Posts: 755	Thanks Dan - yes the white balance pic was far more natural (without it looked pretty garish - the subject's face is almost orange - although he's naturally darker skinned which presented a new challenge for me - there is a skin parameter on the HD100 but I was too concerned with other things to use that). I'm glad you feel the true white balance works better - I'll just have to brighten up the key/fill next time and brighten this in post. Should've added - the third pic was just a snap of the makeshift flori (taken with a digi still cam). I'd attached ringlets to the material and stretched them, but being slightly under pressure last night I forgot to weight them down (I'll matte out the creases in this footage). I'll probably invest in a pro set up (although not that expensive via ebay) should I get a run of jobs from this one. I was impressed with myself bearing in mind the amount of skills I pulled together here (first real indoor/studio set up outside of my own tests...I kept a cool head on (not so easy under that 500w halogen) and the potential client looked impressed. Many thanks.

June 5th, 2008, 09:38 AM	#51
Daniel Epstein Trustee Join Date: Jan 2006 Location: New York, NY Posts: 1,267	In my opinion the wrinkles left on the Jpg are not as much of a concern as the overall lighting of the background. The background should be lit much flatter with as few shadows as possible. Your keyer may be able to deal with this as this is a chroma key not a luminance key but you want to make the background one color and the shadows could get your green out of range of the keyer.