Greenscreen & Swimming Pool

[PJ Gallagher]

Some filmmaking friends just came to me asking for my thoughts on something they're proposing to do. They're most of the way through shooting a low-budget feature, a Jaws-type story set in a local lake. They've shot some of the finale sequences, which take place on the lake at night, but the lake has now been closed for the forseeable future due to blue-green algae outbreaks, and plus we're now heading into winter here, and the temperature is dropping sharply.

So, their proposal is to complete the scene in a swimming pool, greenscreening in the city lights in the background. This immediately rang all sorts of problem bells for me, but I thought somebody here might have thoughts on how this might be done.

Here are the problems that occurred to me:

- The main one is that from what I understand the scene is at night. This means that the actors and surrounds will have to be fairly darkly lit, but the greenscreen will need to be brightly lit. As a result, there will be a massive amount of green reflection in the water, which would make compositing an absolute nightmare.

- The lake is murky. The swimming pool is crystal clear. If you shoot at a downward angle, you'll see the (most likely white or bright blue) bottom of the pool. Shoot towards the sides and you'll likely see the side.

- If you did go greenscreen, you'd need to drape the material right into the waterline, meaning you need to either find your own greenscreen material, or someone who's willing to risk having their material ruined. And you would likely need a fairly large greenscreen to get the required separation.

Thoughts?

Cheers
Pat

[Mark Keck]

I'm no expert on this, so perhaps some one who is will pipe up. But here's an idea... shoot in the pool at night with as low an angle as possible so as to avoid the bottom problem, and roto out everything from the waters edge on up. I know... a lot of work. But it'll get the scene to approximate reality, and with some good cc might even be believable.

Good luck,

Mark

[Scott Timothy Wilson]

How'd you make out with this shot? I'd love to see the final outcome! If you shot it at night I don't even know if you'd need to put the green screen into the water, i wouldn't think you could see the other pool wall in the night. But as for light reflecting off the green screen into the water...that could get ugly. A polarizing lens might help reduce reflection from the water. maybe adding a non-green colored pool light would help??