Green Screen

Hi all

Has anyone ever used, or attempted to use a green screen underwater? I'm wondering if it would be possible to stop the material moving in the water and if not whether the movement would effect the quality of the background. Maybe paste the screen to a board? This is for a shoot in a pool, not in the sea so there are no problems with currents or other water movement. Of course there may be a fundamental problem trying to use a green screen in the water anyway (I'm assuming that a blue screen is a non starter) so it may not even be possible. But hey, if you don't ask.....

Cheers, Simon

WHAT THE !!!!!

You aint going to fool those judges at Antibes bro... They will tell its you by the wobbly, out of focus shooting..lol..

But no I dont know anyone who has... Phone up Pinewood or even Extreme Facilities... I think they shoot underwater sequences in giant pools.. They might know...???

Dive safe

DeanB

You aint going to fool those judges at Antibes bro... They will tell its you by the wobbly, out of focus shooting..lol..

 

DeanB

haha yeah now if I can just learn NOT to white balance then I maybe able to get a job with your buddies at the NHU....

Cheers, Simon

Hey Simon,

I was involved in a green screen shoot recently (on surface) and one of the most important factors is getting the lighting right so that the green can be keyed out later. Do you have access to underwater lighting which isn't attached to the camera? If you get hold of some I reckon it will look heaps better, also lighting above the pool will play a big part I would imagine.

Good luck mate,

Jon

Thanks Jon

I think you can get some special lights/filters that like you said help with keying out the green afterwards but I'll be filming near the surface in daylight in an outside pool, so I'm not confident that they would have any effect as they will almost certainly be overpowered by sunlight. It may not be possible, which would mean back to the drawing board....

Cheers, Simon

I've done blue screen keying on some footage, messing around combining sharks with mantas etc... It looked ok, and might be worth trying depending on the colour of your subject.

If it for commercial use though you'll probably have to buy the lights etc mentioned above.

A buddy did the work for a HBO series and used lights with green screen in a pool. The idea is to make it look like daylight and kill the shadows on the screen. The other this is to make sure your subjects wear contrasting colors to green. Dark colors work well but may not be esthetically pleasing.

If you are shooting daylight in a pool, then you can use the most constant background (pool wall WITHOUT light fixtures, tiles etc etc and key that out. Then you can use a matte to remove the other crap. For quick and dirty, Red Giant's Primatte Keyer has been mentioned to me a few times. I've only seen great results from Imagica's Primatte but that's top end. Adobe AE is the better keyer of the popular software available.

I just did it to 88 uptop clips.

Used my NLE's chrominance filter to change the background wall we shot against, was pretty easy to do.

I suppose underwater one would just need the water to be pretty clear for a start.

I have tried to "blue screen" out water and background to cut out a subject in post using a matte. Trouble is b/c of rapid color spectrum falloff underwater, just about everything underwater has a blueish tint to it. That means parts of your subject get screened out as well. Even in very clear water this can be the case. One way around this could be to spotlight your subject, making sure all surfaces are hit by the lights and make sure your suject has no blue (standard blue/green screen procedure). Then ensure you have enough distance from the pool walls such that the back ground is uniformly blue (as much as possible). Advantage of this method is you need only enough light to hit your subject.

Problem with these types of matte procedures in post is that most likely parts of your subject will be selected in the matte at "random" and edges will likely be quite soft. For professional work, this may not cut it. I suggest experimenting in the pool of course.

-shawn

Hey Simon,

I was involved in a green screen shoot recently (on surface) and one of the most important factors is getting the lighting right so that the green can be keyed out later. Do you have access to underwater lighting which isn't attached to the camera? If you get hold of some I reckon it will look heaps better, also lighting above the pool will play a big part I would imagine.

 

Good luck mate,

 

Jon

For television productions we have to have the green(or blue) screen 2 stops higher than you subject and foreground in order to key in properly.You will need very powerful lights to put under water.I assume this is for a production and not just for fun sake.

Hi all and thanks for the advice, I'll experiment a bit and see if I can get away without using additional lights initially. Yes it is for commercial use but the erm, ah, 'models' wont be wearing anything so no problems with colour clashes. (That sounds a hell of a lot worse than it actually is by the way so clean up your dirty minds!!)

Cheers, Simon

'models' wont be wearing anything so no problems with colour clashes.

Cheers, Simon

Do you need a tea maker, second camera, sweeper upper...tissue holder ( ) shoulder to cry on....?????

Dive safe

DeanB

Do you need a tea maker, second camera, sweeper upper...tissue holder ( ) shoulder to cry on....?????

 

Dive safe

 

DeanB

Had a feeling you wouldd be back in this thread when you heard no clothes More reliable than betting on the sun rising in the morning

More reliable than betting on the sun rising in the morning

Awwww sorry to be so obvious.... But at your age your 'sun' or whatever you choose to call it is not really that reliable...

Dive safe

DeanB

Awwww sorry to be so obvious.... But at your age your 'sun' or whatever you choose to call it is not really that reliable...

 

Dive safe

 

DeanB

You know when I lob you a softball you should say thanks

Thanks...

Dive safe

DeanB

For television productions we have to have the green(or blue) screen 2 stops higher than you subject and foreground in order to key in properly.You will need very powerful lights to put under water.I assume this is for a production and not just for fun sake.

Definitely, especially for hardware keyers used in broadcast. I suspect Simon will have to do quite a bit of post work.

Yes it is for commercial use but the erm, ah, 'models' wont be wearing anything so no problems with colour clashes.

You'd be very surprised how well software can matte without a greenscreen even. It just takes time. The other thing to watch out for is ripples on the skin from sunlight hitting the water. Controlling your lighting will be key. I suggest you check demos of Imagica's Primatte and Red Giant's Primatte Keyer.

Couple of things to keep in mind - keying in anything less than DVCPro50 is a bitch. If you're shooting DV 25, and even some forms of HDV, it's really impossible to pull a good key. Second thing is that if you're planning a daylight shoot, even the slightest bit of movement on the surface is going to cause a ripple, and we all know how that works out with rays of sunlight underwater. I'd go for an indoor pool and use the biggest lights you can on the surface to light the background. Any change in color on any frame of the background is going to wreck your key. Also, Primatte RT is probably the best key plug in out there, but I've had really, really good luck with DV Matte Blast from DV Garage. http://www.dvgarage.com/

I acted in a TV commercial on Friday in front of a blue screen at their studio. While I have done some topside keying work on my own, I was impressed with the perfect, shadowless lighting they achieved. It was my first time using a teleprompter as well.

I have been able to achieve keying effects by using Final Cut Pro's composite modes, a feature that is often ignored by FC users who barely know it is there. Try it and you might be able to get the effect you want without painting all the rocks,kelp and passing fish the same shade of green.

On another note, what's the big deal with Antibes? I'm sure many of the films entered are excellent but I know they show some films that look as if they were shot and edited by someone who was holding a cam for the first time. To me, that certainly lessens the prestige of having a film accepted.

Steve

hi simon,

just wondering, would diffused green gels on backlighitng work? this would potentially create the green halo around the subject that would then

key out....

just a thought....

mark.