A quick test for Marek, zombie hands under water, uploaded on Apr 17, 2014
About 2 hours to make, including photography and compositing. The first few versions just show a basic layer composite, nothing fancy. Could work if the hand is “under” the ice. The last two use a simple luma matte without much tweaking (and thus artifacts), filters and a tiny bit of roto for the chunk of ice moving over. Later, a second piece of ice moves under the hand – no roto. Final version would require 1+ day of dedicated production.
Marek wanted hands reaching up from the depths. How that might work.
Bare arms airbrushed with matte green, soft edge builds to sold green near elbow. Fingertips toward camera and slight air draft blown from side of arms simulates water flow, either constant or cyclical like waves. Actors perform the flow. In theory, ramped green becomes a depth matte, fading the arms into the depths of the water/fog/shadows. Might have to shoot arms individually and then composite to fully light the green from all sides.