---
title: "Spill Suppression"
slug: "spill-suppression"
updated: 2026-02-26T08:02:35Z
published: 2026-02-26T08:02:35Z
---

> ## Documentation Index
> Fetch the complete documentation index at: https://composer.docs.vindral.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Spill Suppression

The **Spill Suppression** operator removes green or blue color contamination from chroma key footage. When filming against a green or blue screen, the screen color often reflects onto the subject's hair, skin, clothing, and other surfaces. This filter detects and removes that color "spill" while optionally replacing it with a more natural tone.

![Image](https://cdn.document360.io/94808959-fd66-406c-ab5e-4691ce952a14/Images/Documentation/image(246).png){height="" width=""}

---

## Overview

Spill occurs because:
- Light bounces off the green/blue screen onto the subject
- Semi-transparent materials (hair, fabric edges) pick up the screen color
- The screen color bleeds into edge pixels during keying

Spill suppression works by detecting where the green (or blue) channel is abnormally high compared to the other channels, then reducing it to a natural level.

---

## Quick Start

1. Add the **Spill Suppression** operator after your chroma key effect
2. Select **Screen type** (Green or Blue) to match your footage
3. Adjust **Amount** to control overall suppression strength
4. Use **Show spill map** to visualize detected spill areas
5. Fine-tune with **Method** and **Replace mode** for best results

---

## Settings

### Screen

| Setting | Description |
|---------|-------------|
| **Screen type** | The color of your chroma key screen - Green or Blue. |

### Suppression

| Setting | Description |
|---------|-------------|
| **Amount (%)** | Overall spill suppression strength. 0% = no suppression, 100% = full suppression. |
| **Method** | Algorithm for detecting spill. See Suppression Methods below. |
| **Core strength (%)** | Suppression intensity on obviously spilled areas (strong green/blue contamination). |
| **Edge strength (%)** | Suppression intensity on subtle edge spill. Often needs to be lower to avoid artifacts. |

#### Suppression Methods

| Method | Description |
|--------|-------------|
| **Light** | Subtle suppression. Green/blue shouldn't exceed the maximum of the other two channels. Good for minor spill. |
| **Medium** | Balanced suppression. Green/blue shouldn't exceed the average of the other channels. Best general-purpose option. |
| **Aggressive** | Strong suppression. Uses a weighted average that's more restrictive. Good for heavy spill. |
| **Max** | Maximum suppression. Green/blue shouldn't exceed the minimum of the other channels. Can cause color shifts on legitimate green/blue objects. |

### Spill Replacement

When spill is removed, you can optionally replace it with another color to compensate for the lost luminance and maintain natural skin tones.

| Setting | Description |
|---------|-------------|
| **Replace mode** | What to do with removed spill. See Replace Modes below. |
| **Tint strength (%)** | How strongly to apply the replacement color. |
| **Replace color (R/G/B)** | Custom replacement color when using Custom mode. |

#### Replace Modes

| Mode | Description |
|------|-------------|
| **None** | Just remove spill without replacement. Can darken affected areas. |
| **Gray** | Add neutral gray to compensate. Maintains luminance without color shift. |
| **Complement** | Add the complementary color (magenta for green, yellow for blue). Most natural-looking for skin. |
| **Custom** | Blend toward a custom color. Useful for specific color correction needs. |

### Fine Tuning (Advanced)

| Setting | Description |
|---------|-------------|
| **Spill range (%)** | How sensitive the spill detection is. Higher values detect more subtle spill but may affect legitimate colors. |
| **Protect skin tones** | Reduces suppression on detected skin tones to prevent unnatural color shifts. Recommended to keep ON. |
| **Preserve luminance (%)** | Maintains original brightness after suppression. Prevents darkening of affected areas. |

### Output

| Setting | Description |
|---------|-------------|
| **Output mode** | What to display. See Output Modes below. |

#### Output Modes

| Mode | Description |
|------|-------------|
| **Final** | The processed result with spill suppression and alpha adjustment applied. |
| **Foreground** | The original input image before any processing. |
| **Spill Map** | Colored visualization of detected spill (green or blue depending on screen type). |
| **Alpha** | Grayscale view of the alpha channel, including any alpha adjustments. |
| **Spill Matte** | Grayscale visualization showing the amount of spill detected per pixel. |

### Alpha Adjustment (Advanced)

These settings reduce the alpha channel in areas where spill is detected. This makes spill areas more transparent, which is useful for cleaning up semi-transparent edges (like hair) or removing fringe artifacts.

| Setting | Description |
|---------|-------------|
| **Alpha adjust (%)** | Maximum alpha reduction in spill areas. 0% = no change, 100% = fully transparent where spill is strongest. |
| **Alpha threshold (%)** | Minimum spill level required before alpha is affected. 0% = any spill affects alpha, higher = only strong spill affects alpha. |
| **Alpha softness (%)** | Transition range above threshold. 0% = hard cutoff, higher = gradual transition from no effect to full effect. |

**How it works:**
1. The filter detects spill amount per pixel (visible in Spill Matte output mode)
2. If spill > threshold, alpha reduction begins
3. Softness controls how gradually the effect ramps up
4. Alpha adjust controls the maximum reduction at full effect

---

## Keyboard Shortcuts

| Key | Function |
|-----|----------|
| **F1** | Toggle Green/Blue screen type |
| **F2** | Cycle through suppression methods |
| **F3** | Cycle through replace modes |
| **F4** | Toggle protect skin tones |
| **F5** | Cycle through output modes |

---

## Workflow Guide

### Step 1: Identify Spill

1. Enable **Show spill map** to see where spill is detected
2. Bright areas indicate strong spill
3. If spill map doesn't match visible spill, adjust **Spill range**

### Step 2: Choose Method

Start with **Medium** method, then:
- If spill remains: Try **Aggressive** or **Max**
- If colors look wrong: Try **Light**

### Step 3: Adjust Strength

1. Set **Core strength** high (80-100%) for obvious spill
2. Set **Edge strength** lower (30-60%) to preserve edge detail
3. Adjust **Amount** for overall control

### Step 4: Color Compensation

1. If skin looks gray/dead: Use **Complement** replace mode
2. Increase **Tint strength** until skin looks natural
3. Enable **Preserve luminance** to prevent darkening

### Step 5: Alpha Adjustment (Optional)

If you have semi-transparent edges that look too solid due to spill:

1. Set **Output mode** to **Alpha** to see the current alpha channel
2. Increase **Alpha adjust** gradually (start with 20-40%)
3. Adjust **Alpha threshold** to only affect spill areas
4. Use **Alpha softness** for smooth transitions
5. Switch back to **Final** to see the result

### Step 6: Final Tweaks

1. Enable **Protect skin tones** if not already on
2. Zoom in on hair and fabric edges to check for artifacts
3. Compare with original to ensure no over-correction

---

## Common Scenarios

### Hair Fringe / Flyaway Hair

Hair edges often pick up significant spill:
- Use **Medium** or **Aggressive** method
- Keep **Edge strength** moderate to preserve detail
- **Complement** replace mode helps maintain natural hair color

### Skin Near Screen Edge

When skin is close to the screen, it can pick up green/blue cast:
- Enable **Protect skin tones**
- Use **Complement** replace mode
- Increase **Tint strength** for natural skin

### White or Light Clothing

White fabrics easily pick up spill:
- **Medium** method usually works well
- Use **Gray** replace mode to maintain neutral whites
- High **Preserve luminance** to keep brightness

### Transparent/Translucent Objects

Glass, plastic, fabric with transparency:
- Often needs **Aggressive** method
- May need to accept some spill on truly transparent areas
- Consider masking and treating separately

---

## Troubleshooting

| Problem | Solution |
|---------|----------|
| **Skin looks magenta/purple** | Reduce **Tint strength**, or switch to **Gray** replace mode |
| **Skin looks gray/lifeless** | Enable **Complement** mode, increase **Tint strength** |
| **Spill still visible** | Increase **Amount**, try **Aggressive** method, increase **Spill range** |
| **Legitimate green/blue objects affected** | Lower **Spill range**, use **Light** method, or mask those objects |
| **Dark edges after suppression** | Increase **Preserve luminance**, use **Gray** replace mode |
| **Hair looks unnatural** | Reduce **Edge strength**, enable **Protect skin tones** |
| **Spill map shows nothing** | Wrong **Screen type** selected, or very low spill in footage |
| **Edges too transparent after alpha adjust** | Reduce **Alpha adjust**, increase **Alpha threshold** |
| **Alpha adjustment affects wrong areas** | Increase **Alpha threshold**, reduce **Spill range** |

---

## Tips for Best Results

### Prevention at Shoot

- Keep subjects away from the screen (reduces spill)
- Use proper lighting to minimize screen reflection
- Consider spill-suppression lighting (magenta/yellow fill)

### Order of Operations

Apply spill suppression **after** chroma keying but **before**:
- Color correction
- Final compositing
- Other effects

### Multiple Passes

For difficult footage, consider two passes:
1. First pass: **Aggressive** method, low strength, targeting obvious spill
2. Second pass: **Light** method, targeting subtle remaining spill

### Preserve the Original

Keep an unprocessed version of your footage to compare against. Over-suppression can look worse than some spill.

---

## Technical Notes

- Spill detection compares the screen color channel against the other two channels
- Skin tone protection uses hue and saturation analysis to identify skin-colored pixels
- All processing is done per-pixel on the GPU in real-time
- The filter preserves the alpha channel from the input