UVIR Cut / UV-IR Cut Filter / Hot Mirror

nd filter color science sensor

Optical filter that blocks both ultraviolet and infrared light while transmitting visible wavelengths – essential for digital cinema cameras to prevent color contamination, false colors, and focus issues caused by UV and IR light that digital sensors can detect but human eyes cannot.

What is a UVIR Cut Filter?

A UVIR Cut Filter blocks ultraviolet and infrared light while allowing visible wavelengths to pass. It is essential for digital cinema cameras to prevent color distortion caused by UV and IR radiation that sensors can capture.

Basic Principle

Aspect	Description
Definition	UV+IR Blocking Filter
Function	Wavelength Selection
Blocks	UV (<380nm), IR (>700nm)
Transmits	Visible Light

Why Necessary?

Problem	Cause
IR Contamination	Sensor Sensitivity
False Colors	IR in Visible Spectrum
Focus Shift	IR Focuses Differently
UV Haze	Atmospheric UV

IR Contamination

Symptom	Appearance
Black Fabrics	Magenta/Brown
Skin Tones	Discolored
Highlights	Color Cast
Focus	Soft

Affected Situations

Situation	Risk
Strong ND	High
Sunlight	Medium-High
Tungsten	Low
LED	Variable

Filter Types

Type	Characteristic
Hot Mirror	Reflective
Absorptive	Absorbing
Hybrid	Combined
Internal	Camera Integrated

Internal vs. External

Position	Pros/Cons
Internal (OLPF)	Always Active, Limited
Internal (Slot)	Flexible, Modifiable
External (Matte Box)	Swappable
Lens Mount	Permanent

Camera-Specific

Camera	UVIR Situation
ARRI	Internal OLPF
RED	Filter System
Sony Venice	OLPF + Slot
Blackmagic	Varies

ND Combination

ND Type	UVIR Requirement
No ND	Often Minimal
Variable ND	High
Glass ND	Depending on Type
Built-in ND	Camera Dependent

Manufacturers

Brand	Product
Tiffen	T1 IR Filter
Schneider	Platinum IRND
Formatt Hitech	Firecrest
ARRI	FSND (incl. IR)

Specifications

Parameter	Typical
UV Cutoff	~380nm
IR Cutoff	~700nm
Transmission	90%+ Visible
Density	Neutral

Performing Tests

Test Method	Description
Black Fabric	Shoot black fabric
IR Remote	LED visibility
Chart	Color reproduction
A/B Comparison	With/without filter

Workflow

Step	Activity
Prep	Test equipment
On-Set	Use as needed
Monitor	Observe colors
Adjust	Situationally

Combinations

Filter Stack	Consideration
UVIR + ND	Common
UVIR + Polarizer	Possible
UVIR + Diffusion	Order
Multiple	Vignetting

Challenges

Problem	Solution
Reflections	Coating Quality
Vignetting	Thin Filters
Cost	Budget Planning
Consistency	Matching

Best Practices

Practice	Reason
Test	Before Production
Document	Filter Configuration
Backup	Spare Filters
Consistency	Throughout Shoot

Today

UVIR Cut Filters are standard equipment for digital cinematography. With the increasing sensitivity of modern sensors and the prevalence of strong ND filters, IR control is more important than ever. Integration into combined IRND filters has simplified workflows, while separate UVIR cuts offer maximum flexibility.

From the crafts

Perspectives

Cinematographer

UVIR-Cut-Filter sind essentiell bei bestimmten Lichtsituationen und ND-Kombinationen. Ohne sie können digitale Sensoren IR-Kontamination zeigen, besonders bei schwarzen Stoffen, die dann magenta erscheinen.

Director

UVIR-Filter sind ein technisches Detail, das die Bildqualität sichert. Ich verlasse mich auf meinen DP, diese Entscheidungen zu treffen – das Ergebnis sind natürliche, korrekte Farben.

Producer

UVIR-Filter sind Teil der Standard-Kameraausrüstung. Die kleinen Kosten verhindern teure Farbkorrekturen in der Post, die durch IR-Kontamination entstehen können.