CTO-033 Color Temperature Orange (Warming) Filter
Full CTO colour-conversion filter shifting 5600 K toward 3200 K for seamless mixed-lighting balance in broadcast, film, and architectural applications.
- Colour shift direction: Warming (5600 K → 3200 K)
- Mired shift: +131 Mired
- Correction strength: Full CTO
- Average transmittance: ~41.2 % T (visible range)
- Peak transmittance: ~95.1 % T near 727 nm
- Minimum transmittance: ~2.7 % T near 440 nm
- Construction: Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick
- Custom options: Intermediate Mired shifts, combined CTO+diffusion, custom sizes, rapid prototypes
Learn more
CTO-033 delivers a +131 Mired shift to move 5600 K light toward 3200 K. Its smooth spectral slope creates a natural warming effect, with about 41.2 % average visible transmittance and approximately 1.5 stops of light loss.
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Full daylight-to-tungsten conversion on HMI or daylight LED fixtures, mixed-light interiors, and scenes that need a strong warm match.
Description
CTO-033 provides a deep warm shift with its 50 % crossover at 638 nm, passing red and near-infrared while strongly suppressing shorter wavelengths. Blue averages just 14.3 %, green 12 %, and yellow 16.4 %, while red climbs to 71.6 % and NIR reaches 82.5 %. Peak transmission of 95.1 % at 727 nm places the efficiency maximum in the far red. A brief dip below 5 % between 427-455 nm adds a secondary blocking feature in the deep blue. The overall profile delivers a saturated red-orange output from any broadband source.
Key Advantages
- 50 % crossover at 638 nm - defines a deep warm transition that passes primarily red and NIR wavelengths.
- Peak of 95.1 % at 727 nm - provides high throughput in the far red for efficient deep-warm lighting.
- Broad cool-tone suppression (blue avg 14 %, green avg 12 %) - delivers a saturated warm output with minimal cool contamination.
- Hard-oxide durability - ion-assisted coating withstands high lamp heat, humidity, solvents, and cleaning.
- Custom formats available - round, square, or free-form blanks from 5 mm to 450 mm, thickness 0.21-3.8 mm, on Borofloat®, soda-lime, Schott D263 T, or Corning Eagle XG substrates.
Typical Applications
- Stage and concert lighting - produces saturated red-orange washes for dramatic sunset, fire, and warm-interior scenes.
- Film and broadcast warm effects - provides heavy colour-temperature conversion for deeply warm set lighting and practical lamp simulation.
- Architectural and museum lighting - transforms neutral sources into warm amber-red accents for heritage and gallery environments.
- Machine vision and sensing - functions as a deep-red longpass for applications requiring red-NIR illumination with strong visible-light rejection.
- Horticulture spectral shaping - emphasises the red and far-red photosynthetically active wavelengths while rejecting blue and green.
Need prototypes in days or production volumes next quarter? CTO-033 filters can be coated, diced, and shipped to your exact specifications.
FAQ
CTO-033 FAQ
What is CTO-033 and what is it used for?
CTO-033 is a Color Temperature Orange Filter - Deep Warm Shift (T50 % = 638 nm). CTO-033 provides a deep warm shift with its 50 % crossover at 638 nm, passing red and near-infrared while strongly suppressing shorter wavelengths. Blue averages just 14.3 %, green 12 %, and yellow 16.4 %, while red climbs to 71.6 % and NIR reaches 82.5 %. Common uses include Stage and concert lighting, Film and broadcast warm effects, Architectural and museum lighting, and Machine vision and sensing.
What are the key optical specs of CTO-033?
Key published specs for CTO-033 include Colour shift direction: Warming (5600 K → 3200 K); Mired shift: +131 Mired; Correction strength: Full CTO; Average transmittance: ~41.2 % T (visible range); Peak transmittance: ~95.1 % T near 727 nm.
What applications is CTO-033 best suited for?
CTO-033 is commonly used for Stage and concert lighting, Film and broadcast warm effects, Architectural and museum lighting, and Machine vision and sensing. Stage and concert lighting - produces saturated red-orange washes for dramatic sunset, fire, and warm-interior scenes.
Can CTO-033 be customized for size, substrate, or coating requirements?
KUPO lists the construction for CTO-033 as Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick. Published custom options include Intermediate Mired shifts, combined CTO+diffusion, custom sizes, rapid prototypes. Custom formats available - round, square, or free-form blanks from 5 mm to 450 mm, thickness 0.21-3.8 mm, on Borofloat®, soda-lime, Schott D263 T, or Corning Eagle XG substrates.
What should I know about angle of incidence and durability for CTO-033?
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
