Resolve FX · ColorDaVinci Resolve 21

Despill

A focused colour-cleanup Resolve FX for removing red, green or blue screen spill that remains on a subject after keying, matting or rotoscoping.

Key Color

Red / Green / Blue

Strength

Despill amount

Global Blend

Final mix

What Despill actually does

It removes reflected screen colour — it does not create or repair the key

A green or blue background can illuminate the subject and leave coloured contamination on hair, skin, transparent fabric and reflective edges even after the background itself has been keyed out. The standalone Despill Resolve FX targets that remaining cast.

What it solves

Green/blue/red reflection that remains on the subject after the matte exists.

What it does not solve

Bad alpha edges, missing hair detail, holes, chatter or a poorly isolated background.

Why standalone matters

It can be placed after an existing key, matte or roto and adjusted independently from the key itself.

Panel controls

Three controls, but each solves a different stage of the cleanup

Set the spill colour first, tune the suppression amount second, and use Global Blend only after the effect is already technically correct.

Which spill to remove

Key Color

Key Color defines the colour channel that Despill should suppress. Resolve offers Red, Green and Blue. For conventional chroma keying, choose the screen colour: Green for green screen and Blue for blue screen. Red is useful in unusual cases where the contamination is genuinely red. This is not an arbitrary colour picker; the effect works from the three primary choices.

Green — the standard green-screen spill case
Blue — spill from a blue screen
Red — less common non-standard cases

Neutralisation amount

Strength

Strength controls how strongly Resolve removes the selected spill. A value of 1.000 corresponds to the full despill action; lower values preserve more of the original colour information. This matters on skin, hair, translucent fabric and reflective edges, where aggressive green or blue suppression can make colour look grey, magenta or unnaturally warm.

Do not automatically assume 1.000 is best
Judge contaminated edges and skin first
A lower value often preserves natural hue better

Final effect mix

Global Blend

Blend mixes the final Despill result with the node's original state. It is useful as a final safety control once the basic setting is already correct but the correction feels slightly too sterile. Blend and Strength are not identical: Strength changes the despill calculation itself, while Global Blend mixes the already computed result back with the original.

Set Key Color and Strength first, Blend last
Blend cannot fix the wrong Key Color
Compare across motion, especially hair and motion blur

Despill vs neighbouring tools

Do not ask colour cleanup to solve a matte problem

Despill

Suppresses reflected red/green/blue screen colour after the subject has already been isolated.

3D Keyer

Builds the chroma key/matte and also includes its own despill workflow; use it when the key itself still needs work.

Qualifier / Window

Restricts where Despill is allowed to act when legitimate scene colour resembles the selected Key Color.

Primaries / Curves

General colour balancing for the shot. They are not a dedicated screen-spill model and can disturb unaffected regions.

Production workflow

A six-step Despill workflow for clean edges without dead colour

Treat spill as a colour contamination problem after the key. Fix the matte first, select the correct channel, then remove only as much contamination as the shot actually needs.

Confirm that the problem is spill, not a bad key

Spill is coloured light reflected from the screen onto the subject. Despill can clean that colour cast, but it does not rebuild a broken matte, recover missing hair detail or repair chatter on the alpha edge.

Choose the screen colour in Key Color

Use Green for green-screen contamination, Blue for blue-screen contamination, and Red only when the unwanted reflected cast is genuinely red. Do not choose a colour merely because the subject contains it.

Raise Strength while watching the contaminated edges

Start below the maximum and increase until the green/blue edge contamination stops attracting attention. Hair, skin, translucent fabric and metallic reflections are the first areas where excessive despill becomes obvious.

Check real colours that resemble the key colour

A green garment, blue prop or coloured practical can be legitimate scene colour. If Despill weakens it, isolate the subject region more precisely with a node matte, Window, Qualifier or the keyer's own routing rather than simply pushing Strength lower everywhere.

Validate skin and channel balance

Use the Viewer, RGB Parade and Vectorscope together. The goal is not to force numerical neutrality; it is to remove the reflected screen cast without turning believable skin or edge colour into a different hue.

Use Global Blend only as the finishing trim

Once Key Color and Strength are correct, reduce Blend only if the effect still feels a little too clean. Review the full moving shot before finalising because spill changes with pose, hair motion and the subject's distance from the screen.

Common failures

Most bad Despill results are either over-cleaned colour or a matte problem in disguise

Symptom

Skin becomes grey or magenta

Cause: Strength is too high and genuine green/blue contribution in the skin or reflected environment is being suppressed along with the unwanted spill.

Fix: Back Strength down first. If only one region still needs stronger cleanup, isolate that region rather than increasing the global amount.

Symptom

The screen is keyed out but a green rim remains

Cause: The matte removed the background but bounced green light is still physically present in hair, skin or semitransparent edges.

Fix: This is exactly the intended Despill case: choose Green and raise Strength until the rim becomes believable, then inspect hair detail and skin.

Symptom

A real green or blue object loses colour

Cause: Despill is being applied to image content that contains legitimate colour similar to the chosen Key Color.

Fix: Constrain the FX spatially or through the subject matte. Do not expect a standalone despill filter to know which green/blue belongs to the screen and which belongs to the production design.

Symptom

The edge colour changes from frame to frame

Cause: The amount of physical spill varies with motion, distance to the screen, changing reflections or a matte that exposes different edge pixels over time.

Fix: Judge the whole clip, not one still. Stabilise the matte first if needed, then choose a conservative Strength or keyframe the node/effect only when the shot genuinely requires it.

Colour cleanup after the key, not the key itself

Despill: the signal-level model

The most useful mental model for Despill is post-key colour cleanup. A chroma key removes the background through a matte, but physically reflected screen light can remain in the subject's RGB values — especially in hair, skin, translucent materials and reflective edges. Despill suppresses the selected red/green/blue contamination without rebuilding the matte.

Blackmagic's Reference Manual describes the standalone Despill filter as a way to remove colour cast left on a subject by reflected green/blue-screen light after the background has already been keyed out. It is also explicitly useful for already keyed, matted or rotoscoped footage and for keying plugins that do not provide their own despill.

Standalone Despill does not understand production-design semantics. If the frame contains legitimate green, blue or red wardrobe/props resembling the selected Key Color, the effect can alter them along with the spill. Spatial or matte isolation remains the responsibility of the node tree.

Use it when

green/blue-screen footage where the key already exists but coloured contamination remains on hair, skin or edges
finished alpha/matte/roto elements that need independent screen-spill cleanup without re-keying
keying plugins or upstream composites that do not provide a suitable despill control

Choose another tool when

the main problem is a bad matte, chatter, holes, missing hair or a hard alpha edge: fix the key first
the shot needs general white-balance/colour correction rather than screen-spill suppression
legitimate subject colour matches the Key Color and cannot be reliably isolated with a matte/window/qualifier

Control → signal meaning → verification

Layer	What it means	How to verify
Key Color	Selects which primary spill channel to suppress: Red, Green or Blue. In chroma-key work this normally matches the physical screen colour.	Match the real contamination source. Green screen → Green, blue screen → Blue; use Red only for genuinely red spill.
Strength	Amount of Despill. 1.000 corresponds to the full despill action; lower values preserve more of the original colour information.	Inspect skin hue, hair translucency, reflective edges and legitimate colours near the selected channel; over-despill often appears as grey/magenta/warm shifts.
Global Blend	Mixes the computed Despill output with the node's original state. This is a post-effect mix, not a spill-channel selection.	Set Key Color and Strength at Blend 1.000, then use Blend only as a final perceptual trim.
Matte / spatial isolation	Not a parameter of the FX itself, but it determines where Despill is allowed to alter RGB. This is critical when legitimate green/blue/red objects exist.	Inspect alpha/matte and RGB together; if legitimate object colour is affected outside the contaminated edge, restrict the node key/window/qualifier.

Production workflow

01Stabilise the key/matte first: Despill should not be compensating for chatter, holes or an incorrect edge.
02Identify the physical spill source and choose Red, Green or Blue in Key Color.
03At Blend 1.000, gradually raise Strength while judging contaminated hair/skin/edges in motion.
04Check legitimate subject colours resembling the Key Color; constrain the FX with a matte/window/qualifier when needed.
05Use RGB Parade/Vectorscope to support Viewer judgement, then trim Global Blend and review the full shot.

Diagnostics: symptom → cause → fix

The green rim disappears but skin becomes magenta/grey

Likely cause: Strength is too high and is removing legitimate colour information along with the spill.

Fix: Reduce Strength; if stronger cleanup is needed only at the edges, constrain Despill with an appropriate matte/Window.

A green fringe remains after Despill

Likely cause: Strength is insufficient, Key Color is wrong, or the fringe is partly a matte/edge problem rather than colour spill.

Fix: Verify Green/Blue selection, temporarily raise Strength for diagnosis and inspect the alpha edge separately. If the fringe follows the matte, repair the key.

A green garment or blue prop loses saturation

Likely cause: The standalone FX is acting on legitimate colour resembling the selected Key Color.

Fix: Feed the subject matte into the node, constrain the area with a Window/Qualifier, or separate despill and production-colour restoration across nodes.

Colour cleanup pumps as hair moves

Likely cause: The mix of foreground, semitransparent edge and background spill is changing, or the upstream matte itself is unstable.

Fix: Check matte stability first, then choose a conservative Strength; keyframe only when the shot genuinely requires varying cleanup.

Node placement

Despill generally belongs after key/matte generation and before creative colour shaping that could hide the spill. On the Color page it is often a dedicated labelled node receiving the correct subject matte. If the key was created upstream in Fusion/compound/alpha workflows, standalone Despill can be applied to the already keyed RGB+alpha element.

Scopes / validation

The Viewer remains primary because despill is perceptual edge/skin cleanup. RGB Parade helps reveal excessive channel suppression, while Vectorscope exposes unwanted skin hue/saturation shifts. Alpha/matte view is also required so a colour problem is not confused with a key problem.

Managed-pipeline warning

Despill is not a colour-management transform and does not replace RCM/ACES technical conversion. It should still operate on a correctly normalised grading signal. Do not use it to compensate for wrong gamma, a double transform or a general white-balance error.

Do not confuse the roles

Despill versus the neighbouring Color FX

Color Space Transform

explicit conversion between colour-space/gamma descriptions, including tone/gamut mapping

Despill

It removes reflected screen colour — it does not create or repair the key

What it solves

What it does not solve

Why standalone matters

Three controls, but each solves a different stage of the cleanup

Key Color

Strength

Global Blend

Do not ask colour cleanup to solve a matte problem

Despill

3D Keyer

Qualifier / Window

Primaries / Curves

A six-step Despill workflow for clean edges without dead colour

Confirm that the problem is spill, not a bad key

Choose the screen colour in Key Color

Raise Strength while watching the contaminated edges

Check real colours that resemble the key colour

Validate skin and channel balance

Use Global Blend only as the finishing trim

Most bad Despill results are either over-cleaned colour or a matte problem in disguise

Skin becomes grey or magenta

The screen is keyed out but a green rim remains

A real green or blue object loses colour

The edge colour changes from frame to frame

Despill: the signal-level model

Use it when

Choose another tool when

Control → signal meaning → verification

Production workflow

Diagnostics: symptom → cause → fix

Node placement

Scopes / validation

Managed-pipeline warning

Despill versus the neighbouring Color FX

Primary references used for this technical layer

Practical questions about Despill in Resolve

Is Despill a keyer?

Why use the standalone effect if the keyer already has despill?

Should Strength always be 1.000?

Can Despill fix a bad green-screen edge?

Where Despill sits in a practical keying and Color workflow

Dehaze

Qualifier / Windows

Scopes

False Color