Clean Plate Node

Unlike classic keying (removing the color), the Clean Plate does the opposite: it keeps as much of the green/blue screen as possible by masking out the subject, then smooths the result to produce an even backing.

Its role: provide a reference plate to the Delta Keyer (magenta input). The keyer then compares each frame with this "ideal" backing to tell the subject from the background even when the lighting is not perfect.

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

A green screen on set is never perfectly even:

• Lights that create hot spots
• Shadows of the subject on the backdrop
• Green reflections on the floor
• Hue variations depending on the distance to camera
• Rig marks, tape, material imperfections

A classic keyer sees all these variations as "almost-green" and produces dirty edges, grain, and bits of background that stay visible. The Clean Plate removes this variability by producing an "ideal" reference - as if there had never been a subject.

• Image Input (orange) - required. The source plate (green/blue screen with the subject).
• Garbage Matte (white) - optional. A mask that excludes non-screen areas from processing (e.g. rigs, floors, areas outside the green).
• Effect Mask (blue) - optional. Limits the clean plate generation to a masked area.

                    ┌→ Clean Plate ─┐
MediaIn (plate) ────┤                ↓ (magenta)
                    └→ Delta Keyer ──→ Merge 2D → Saver

The source plate feeds both the Clean Plate and the Delta Keyer. The Clean Plate generates the backing reference, which is then connected to the Clean Plate input (magenta) of the Delta Keyer.

Method (default: Color)

• Color - for fairly even screens. The most common mode.
• Ranges - for screens with strong shadows or large hue variations. More tolerant.

Matte Threshold

A range slider that rejects values outside the band. It lets you exclude pixels too far from the screen color (deep shadows, blown-out highlights).

Erode

Shrinks the subject mask by removing thin pixels on the edges. Gets rid of small stray non-screen pixels.

Crop

Trims the image from the edges. Useful when the green screen does not reach the edges of the frame.

Grow Edges

Extends the screen color to fill the holes. Key to covering the subject area with the surrounding color.

Fill

Fills the remaining holes with the surrounding screen color. The final step for a complete clean plate.

Sequence

Computes a clean plate per frame. Needed when the lighting changes during the shot (cloud shadow, neon flicker).

Hold Frame

Generates a clean plate from a single frame and applies it to the whole sequence. Faster to render, enough when the lighting is stable.

Rule: Hold Frame by default (faster). Switch to Sequence if you see lighting variations in the shot.

• Improving a poorly lit green screen - use case #1. A shot with hot spots and dark corners → Clean Plate + Delta Keyer gives a much cleaner result than the Delta alone.
• Removing rig marks - a Garbage Matte around the rigs + Clean Plate = a clean backing even with gear visible on the screen.
• A shot on a natural, roughly green background - a green wall, a carpet, photo foam without a pro setup → the Clean Plate compensates for hue variations.
• Removing the subject's cast shadows - the subject's shadows on the backdrop are included in the clean plate, so they are not treated as non-screen pixels.
• A hard key with fine hair - a Clean Plate also improves the recovery of fine edges by giving the Delta Keyer a precise reference.

• Always paired with the Delta Keyer - on its own, the Clean Plate has no direct use. Its output must go into the Clean Plate input of the Delta Keyer.
• Garbage Matte first - remove the non-screen elements (floors, rigs, studio edges) before the Clean Plate reads them as "almost-green".
• Hold Frame for previews - Sequence mode can be slow on a long sequence. Preview in Hold Frame, switch to Sequence for the final render if needed.
• Grow Edges + Fill = the key combo - Grow Edges to extend the backdrop color, Fill to cover the remaining areas. Together they cover the subject area with a plausible color.
• Ranges for difficult screens - shots with strong shadows (floor vs wall, hot spot): switching to Ranges mode gives more tolerance.
• View the clean plate on its own - show the Clean Plate output in a viewer to check that no trace of the subject remains before connecting it to the Delta Keyer.