First of all, let me say that this has been 5 1/2 months in coming. I have finally made available a video that I shot last August for my town’s fire department, which was holding an ALS Ice Bucket Challenge. Hit the jump for the video and a short effects tutorial.
Video on Google Drive: https://drive.google.com/file/d/0B7U0m3_rdpn7dkdnRnMwNHZ5NUU/view?usp=sharing
After watching the video, you probably noticed the obvious: the event took place at night under dim artificial lighting. My ISO levels (which I am unaware of as my K-x doesn’t allow for manual control of ISO and shutter speed during video capture) were extreme, resulting in a lot of noise. To reduce the amount of noise, I chose The Foundry’s Nuke for this task.
Nuke’s noise removal tool is the Degrain node. What Degrain does is sample a noise input to determine the noise pattern, and then use that pattern to remove the noise from another clip. This is often useful for visual effects artists when they want to remove an object in footage based on a still frame, and then add the noise back in, or ‘regrain’ the image.
So to get my source for the noise, I created several ‘grain plates’ using one wall of my porch as a backdrop. I used the one at the highest ISO (smallest aperture), which I estimated at 3200. Next, I brought the footage into Nuke and connected the grain plate to the Noise pipe of the Degrain node and the original clip to the Source pipe. Within the Degrain node properties, I set the Source to Digital and set the analysis box in roughly the center of the frame. Then I merely needed to hit the ‘Analyze Noise’ button for Nuke to calculate the noise. Afterwards, I decreased the High Gain and Luminance Gain and increased the Chrominance Gain to my liking. Finally, I color corrected the shot and rendered it out.
Full-resolution before-and-after frame grabs are included below.
Download the grain plates here.