Under water effect
by addman
on
Jul 26, 2006 at 4:37:42 am
Anyone have any ideas for creating the effct of being under water. We are going to shoot some against a green screen, and then want to add a water ripple effect over the footage. Any ideas?
Re: Under water effect by Mylenium on Jul 26, 2006 at 5:28:32 am
You don't see any rippling underwater. Contiguous volumes of the same substance with constant density do not create any distortion/ refraction whatsoever inside this volume according to the laws of physics. All you would see is some absorbtion (desaturation), light scattering due to micro particles (blur) and a definitive color shift toewards blue (because lower frequencies of the light spectrum get absorbed) in an underwater scene. It is much more important to keep those effects in mind. Use pale makeup and very diffuse lighting. Also add realism by using a fan to create motion in hair and clothes of your talent. Lastly add particle systems for air bubbles and plankton particles.
Re: Under water effect by Troy E. Parker on Jul 26, 2006 at 5:50:24 am
Generally this is correct, but you will see some swirling when passing through Thermoclines (cold/warm water mixing), Haloclines (salt/fresh water mixing) and in very clear water can get a shadow from the surface (clouds, wave action etc) onto a sandy bottom or similar surface.
Re: Under water effect by Dave LaRonde on Jul 26, 2006 at 5:12:37 pm
You might not see rippling under water, but you might see lighting conditions change as the water above the subject ripples.
One way to do this is with a practical effect: put a mirror at the bottom of a BIG container, fill it with water, aim a light on it, blow a fan across the water to ripple it, and train the dancing reflections on the subject.
Yes, it would be a pain to set up, but it could really help to sell the effect visually.
Re: Under water effect by mmhmichael on Jul 27, 2006 at 12:44:04 am
some things to do on set:
-have a fan blowing actors' hair and clothes, then slow down footage in post to normal speed. (creates smooth and slow underwater movement; if you have dialogue/lyrics, have actors perform them at slightly fast speed, then slow down to normal speed in post)
-create light refractions on actors by shining/reflecting light off a ripplng surface of water. also - if you're adventurous - try shining a light through a water tank filled with pieces of foil, glass, or mirrors.
some things to do in post:
-desaturation/hue
-add light refractions/shadows on foreground and background elements
-darken/blur objects further in the background
-add a diffused glow to highlights (with plug-ins; or duplicate a layer, blur it, and screen it over itself)
decide early on what kind of look you're going for - if you want to truly convince the viewer that the footage is underwater, or if you just want to invoke the feeling of being 'under the sea'
