Highly reflective sphere photographed on set to capture environmental lighting – provides 360° HDRI data for accurately lighting CG elements to match live-action footage.
What is a Chrome Ball?
A Chrome Ball (also known as a mirror ball or reference sphere) is a highly polished metal sphere photographed on set to capture ambient light. The reflection provides 360° information for Image-Based Lighting in VFX.
Function
| Aspect | Description |
|---|---|
| Light Capture | Reflects the entire environment |
| HDRI Creation | Basis for Environment Map |
| Lighting Match | CGI matches live-action |
| Reflection Reference | For shiny CG objects |
Technical Specifications
| Property | Standard |
|---|---|
| Material | Polished stainless steel, chrome |
| Surface | Mirror-smooth, no scratches |
| Size | 10–30 cm diameter |
| Reflection | ~100% specular |
On-Set Workflow
| Step | Activity |
|---|---|
| Positioning | In frame where CG will be |
| Height | Eye level or CG position |
| Multiple Exposures | HDR bracket |
| Rotation | Sometimes for 360° |
| Documentation | Time, lighting setup |
Chrome Ball vs. Gray Ball
| Ball | Function |
|---|---|
| Chrome | Light direction and color |
| Gray (18%) | Exposure reference |
| Both | Complete lighting information |
HDRI Creation
| Step | Description |
|---|---|
| Bracketing | Multiple exposures |
| HDR Merge | Into a single HDR image |
| Unwrap | Sphere to panorama |
| Cleanup | Remove tripod, crew |
| Export | EXR, HDR format |
Capture Parameters
| Parameter | Recommendation |
|---|---|
| Exposure | Bracket ±3–5 stops |
| Aperture | f/8–f/11 for sharpness |
| ISO | Base ISO |
| White Balance | Manual, consistent |
| RAW | Always |
Positioning
| Situation | Position |
|---|---|
| Standard | Where CG element will be |
| Creature | Character's eye level |
| Vehicle | Vehicle position |
| Wide Shot | Multiple positions |
Equipment
| Item | Description |
|---|---|
| Chrome Ball | 15–25 cm typical |
| Tripod/Arm | Stable mount |
| Gray Ball | 18% gray |
| Camera | Main camera or DSLR |
| Measuring Tape | For documentation |
Avoiding Errors
| Error | Avoidance |
|---|---|
| Scratches | Protect the ball |
| Incorrect Position | Ask VFX Supervisor |
| Too Few Brackets | More is better |
| Crew in Frame | Communicate clearly |
| Forgetting | Include in shot list |
Software for Processing
| Program | Function |
|---|---|
| HDR Shop | HDRI creation |
| PTGui | Panorama stitching |
| Photoshop | HDR merge |
| Nuke | Unwrap, cleanup |
| Mari/Substance | Create environment |
Alternatives
| Alternative | Application |
|---|---|
| 360° Camera | Fast, but less HDR |
| Panorama Head | Higher resolution |
| Lidar | Combined with lighting |
| Light Probes | Multiple positions |
Cost
| Item | Price |
|---|---|
| Chrome Ball | 50–200 € |
| Gray Ball | 20–50 € |
| Set (both) | 80–250 € |
| Professional Kit | 200–500 € |
Best Practices
| Practice | Reason |
|---|---|
| On every VFX shot | Consistency |
| Before lighting changes | Current state |
| Document | Shot, time, setup |
| Backup | Shoot twice |
Today
The Chrome Ball remains the standard reference for VFX lighting. Despite modern 360° cameras and LIDAR scans, the simple chrome sphere offers fast, reliable lighting information – an essential tool that should be in every VFX kit.
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