Cinematographer
BH-Perforationen sind der Standard für Negativfilm. Die präzise Registrierung ist essentiell für scharfe Bilder, VFX-Arbeit und optische Effekte.
Bell & Howell perforation standard for camera negative film – rectangular perforations with rounded corners optimized for precise pin registration in cameras.
What is BH Perforation?
BH Perforation (Bell & Howell Perforation) is a perforation standard for 35mm camera film. The rectangular holes with rounded corners are optimized for precise pin registration in film cameras.
Technical Specifications
| Parameter | Value |
|---|---|
| Shape | Rectangular, rounded corners |
| Width | 2.794 mm (0.110") |
| Height | 1.829 mm (0.072") |
| Pitch | 4.750 mm (0.187") |
| Corner Radius | 0.508 mm (0.020") |
BH vs. KS Perforation
| Characteristic | BH (Camera) | KS (Print) |
|---|---|---|
| Shape | Rectangular | Rectangular |
| Corners | More rounded | Less rounded |
| Size | Slightly smaller | Slightly larger |
| Usage | Negative film | Positive film |
| Durability | For few passes | For many passes |
Why Different Perforations?
| Reason | Explanation |
|---|---|
| Registration | BH for exact positioning in camera |
| Durability | KS withstands projector wear |
| Tolerances | BH tighter for precision |
| Usage Frequency | Negative: infrequent; Print: frequent |
Application Areas
| Material | Perforation Type |
|---|---|
| Camera Negative | BH |
| Intermediate | BH or KS |
| Release Print | KS |
| Archival Print | BH or Polyester |
Pin Registration
| System | Description |
|---|---|
| Standard Gate | Claws engage perforations |
| Pin-Registered | Additional pins for precision |
| Movement | BH allows tight tolerances |
| Stability | Critical for VFX, Opticals |
Cameras with BH Optimization
| Camera | Registration |
|---|---|
| ARRI 435 | High precision |
| Panavision | Pin-registered available |
| Aaton | Standard BH |
| VistaVision | Horizontal, 8 perfs |
Historical Background
| Year | Development |
|---|---|
| 1908 | Bell & Howell develops standard |
| 1932 | Academy standardization |
| 1950s | KS alternative for prints |
| Today | Standard for negative film |
Quality Control
| Test | Method |
|---|---|
| Pitch | Measurement with gauge |
| Shape | Optical inspection |
| Wear | Edge check |
| Registration | Steadiness test |
Problems and Solutions
| Problem | Cause | Solution |
|---|---|---|
| Blur | Poor registration | Pin-registered gate |
| Wear | Frequent passes | Change material |
| Instability | Worn perforations | New material |
Modern Relevance
| Application | Significance |
|---|---|
| Analog Revival | Standard for new productions |
| Archiving | Understanding for restoration |
| Scanning | Pin registration for best quality |
| VFX | Stability for compositing |
Today
BH perforation remains the standard for 35mm camera negative. Even in the digital age, understanding this specification is important – for analog enthusiasts, archivists, and anyone working with historical film material.
From the crafts
Perspectives
Director
Perforationsstandards sind technische Details, die mein DoP und das Labor koordinieren. Wichtig wird es bei VFX – da brauchen wir maximale Stabilität.
Producer
BH-Perforationen bedeuten höhere Kosten bei Kopierwerk-Prozessen. Für VFX-lastige Produktionen auf Film lohnt sich die Investition in Pin-Registration.
More in the lexikon
Related terms
Camera · Material
KS Perforation / Kodak Standard Perforation / Negative Perf
Kodak Standard perforation – the original rectangular-shaped sprocket hole format for…
Camera · Technique
Film Perforation / Perforations / Sprocket Holes / Perfs
Camera · Equipment
Film Gate / Gate / Aperture Gate / Camera Gate
Test your knowledge
Quiz
1. Zu welchem Department gehört „BH-Perforation"?
2. Wie viele verschiedene Fachperspektiven bietet dieser Eintrag?