Chroma Keyer Node

The Chroma Keyer is Fusion's all-purpose keyer. It is not optimized for a particular kind of backdrop (green or blue), but accepts any color: yellow, red, purple… Useful when you shoot on a non-standard backdrop or want to key an object by its color.

For classic green/blue screen work, the specialized keyers (Delta Keyer, Ultra Keyer, Primatte) give cleaner results with less effort. The Chroma Keyer is still handy for more exotic cases.

• Effects Library: Tools > Matte > Chroma Keyer
• Quick add: right-click in the Node Editor → Add Tool > Matte > Chroma Keyer

• Input (orange) - required. The 2D image containing the color to key (green/ blue screen plate, colored element, etc.).
• Garbage Matte (white) - optional. Makes areas transparent. Useful to get rid of unwanted elements (mic, rig, tripod) that the color key would not remove.
• Solid Matte (green) - optional. Makes areas fully opaque. Useful to protect an area that shares the key color (e.g. blue eyes on a blue backdrop).
• Effect Mask (blue) - optional. Limits the effect after processing.

MediaIn (plate) → Chroma Keyer → Merge 2D → Saver
                          ↑
                    (optional Garbage Matte)

The keyed subject becomes the opaque part, the colored backdrop becomes transparent. Then merge it over a new background.

Standard workflow:

1. In the viewer, drag over the area to key (e.g. the green backdrop). The keyer samples the pixels under the drag to define the color range.
2. Mode:
   • Chroma - selection based on the raw RGB values.
   • Color - selection based on hue. More tolerant of brightness variations.
3. Turn on Lock Color Picking once the initial selection is done so you don't change it by accident when clicking in the viewer.
4. Adjust Soft Range to extend the selection to similar tones.
5. The Reset Color Ranges button starts over without losing the other settings.

Spill = the green or blue reflections from the backdrop that land on the subject (hair, skin, clothes). They need to go for a clean key.

4 suppression levels:

• Rare - the lightest. A subject with little spill.
• Medium - recommended for a standard green screen.
• Well Done - aggressive, recommended for blue screen (blue spills more).
• Burnt - the strongest. For problem shots with a lot of spill.

Rule: Medium for green, Well Done or Burnt for blue. Adjust by testing on the result.

Fringes = the semi-transparent pixels around the outline of the subject (hair edges, smoke). Hard to key without artifacts.

• Gamma / Size / Shape - adjust the halos around the subject. Gamma for density, Size for thickness, Shape for the profile.
• Cyan/Red, Magenta/Green, Yellow/Blue sliders - color corrections on the semi-transparent pixels. Compensate a green halo on the edges by pushing toward Magenta.
• Restore Fringe - brings back hair edges clipped by an overly aggressive key.
• Contract/Expand + Matte Blur - shrinks the matte slightly, then blurs it to soften visible fringing.

Chroma Keyer (this node)

Versatile, accepts any color. Decent but not optimal for standard green/blue.

Delta Keyer

Specialized for green/blue screen, with a higher quality algorithm. Fusion's pro choice for classic keying.

Ultra Keyer

An improved Chroma Keyer with more controls (3 mattes: Fringe, Mask, Clean). Between Chroma and Delta.

Primatte

The reference keyer for broadcast / film. Very powerful for hard cases (imperfect solid backdrop, complex spill). Separate license.

Luma Keyer

Keys by brightness, not by color. To extract bright or dark areas from a black and white image or an isolated channel.

Difference Keyer

Keys by difference with a clean plate (a plate without the subject). For non-colored or complex backgrounds.

Rule: standard green/blue screen → Delta Keyer. Exotic color or simple case → Chroma Keyer. Complex background → Primatte or Difference Keyer.

• Simple green screen on a tight budget - Chroma Keyer + Medium spill is often enough for YouTube or streaming content.
• Keying a colored object on any background - isolate a red fruit, a yellow fabric, etc. The Chroma Keyer shines here, where green/blue keyers do not work.
• Red screen or magenta screen - shoots with an alternative backdrop (e.g. for people wearing green clothes). The Chroma Keyer handles it without a dedicated plugin.
• Cleaning a gradient backdrop - a color that varies across the plate. A Chroma Keyer with a wide Soft Range can follow the variation.
• Protection with a Solid Matte - a subject with blue eyes on a blue backdrop: paint a Solid Matte over the eyes to protect them from the key.

• Lock Color Picking after selecting - otherwise an accidental click in the viewer overwrites the selection.
• Start with a low Soft Range - a strict selection first, then widen it gradually. It avoids keying legitimate pixels of the subject.
• Restore Fringe to bring back hair or edges lost to an overly aggressive key. Very useful in post.
• Contract/Expand + Matte Blur - the classic combo to soften edges without touching the main key.
• Green = Medium, Blue = Burnt - rules of thumb for spill suppression.
• For a hard case (smoke, fine hair, reflections), switch to a Delta Keyer or Primatte. The Chroma Keyer reaches its limits.
• Animated polygon Garbage Matte - draw a polygon around the subject to remove everything outside the clean plate (rigs, floors, etc.). Combine it with the color key.