Nuke W9 – 2D Clean Up (RotoPaint, Grain)

1. Roto Paint (P)

The RotoPaint node gives you a broader scale of tools to use than Roto, though many of the controls are shared across both nodes. It is used to clean up and clone out unwanted elements from the plate. Cons: Heavier than original Roto node

• Clone: Ctrl + click = choose clone source. Shift + drag = change brush size
• Reveal: Reveals the original background after cloning (change paint source from ‘fg’ to ‘bg’ to take effects).
• Paint: Paint/draw on the shot
• Blur, sharpen, smear, dodge, burn: Adjusts the area painted on the shot (similar to Photoshop).
• Dodge for highlight, Burn for shadow

2 ways to separate rotopaint from the plate

• Film grain is the texture in photographic film, caused by small metallic silver particles developed from light-sensitive materials.
• Unlike digital noise, which is electronic interference in digital cameras, film grain is a physical attribute of analog film.
• Grain and noise both impart a comparable appearance, sensation, and texture to filmic images. Techniques utilized for footage from both digital and film sources, such as adding grain, adjusting perspective, and applying denoising, help in creating a scene that feels more natural and organic.

• When working on grainy footages, we will typically start with denoising procedure first. This step is essential to help the tracking of elements that we want to replace in the scene later on.
• Once the editing is completed, grain is re-added to the video to restore its original texture and maintain visual continuity throughout the shot
  
  

• Denoise Node: Link to your source footage the set a bounding box to analyze the existing noise in the footage. After this, you can fine-tune settings like the amount of Denoise, Smoothness, and other parameters.
• Grain Node: Can be quite difficult to match the grain to source footage as you’ll need to go through different RGB channels one by one and adjust settings like grain size, irregularity, and intensity to achieve a close match.
• F_ReGrain Node: Offers a more precise grain matching compared to the Grain node. You connect the grain to the original footage and then link the Src (source) from the shot you are trying to replicate. Note that this is available only in NukeX and is much heavier than Grain node.

DasGrain node

• normalised grain – average denoised, clean plate and cleaned up plate
• common_key = look for the difference between clean plate and cleaned up plate

Homework

I tried to match grain using Grain node by going through RGB channel. I wouldn’t say it looks perfect, especially for Blue channel. But the result seems to be pretty good at the end.