Lighting for water
 

Hi all, I need to do an element shoot on the stage. One of the main things I need to acquire during this shoot is a pouring stream of water. I've never shot a strictly liquid element, so I'm wondering how I should be lighting it.

The element needs to be composited at the end of the day, and I'm pretty certain that I'll need to light it for a luma key. Let the background fall to total black so I'm only picking up the highlights and reflections in the water. The question is: how best to get those highlights? super-powerful backlight? backlights and edgelights? Lit from above? Below? I really don't know.

Is there anybody out there?

VideoMaker magazine suggested taking a shallow pan, breaking a mirror into small pieces, and then filling it with water. You shine your light into the pan, while gently shifting it. This is supposed to simulate water reflecting off of rippling water. Never tried it, because I have never needed this element, but it sounds reasonable.

to get natural water to show up on camera, you need to back light it...the droplets act like little lenses to show off the light hitting it form behind (off to the side a bit is fine so the light doesn't show up in the frame)...I would shoot against a black background, expose for the back/side lit water which will push the background even blacker making it easier to combine later...this would be done using multiply as a composite mode for the water element layer.


diagram:

|cam|<-----|water|-----|backdrop
----------------------\\light crossing water diagonally from rear

I would do as Cole says. When I needed a small stream of water falling and hitting the lens for compositing I followed this setup. A black velvet backdrop with no light hitting it. A stream of water sidelit (with 600 watts from about 2 ft away). The camera in front and below the stream of water, protected from getting wet with a sheet of plexiglass. Make sure you keep the light out of the camera lens and off the backdrop--side light the water only and you will pick it up. The black backdrop, as long as it is really black with no reflections, will work fine for a luma key.

That would be great except for the seven years of bad luck for breaking the mirror. (grin)

-gb-

You might also try a higher than normal shutter speed, making the water more crisp looking.

That's what interns are for ;)