CTO-039 Color Temperature Orange (Warming) Filter
1/2 CTO colour-conversion filter shifting 5600 K toward 3800 K for seamless mixed-lighting balance in broadcast, film, and architectural applications.
- Colour shift direction: Warming (5600 K → 3800 K)
- Mired shift: +67 Mired
- Correction strength: 1/2 CTO
- Average transmittance: ~59.4 % T (visible range)
- Peak transmittance: ~95.4 % T near 632 nm
- Minimum transmittance: ~8.2 % T near 380 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-039 delivers a +67 Mired shift to move 5600 K light toward 3800 K. Its smooth spectral slope creates a natural warming effect, with about 59.4 % average visible transmittance and approximately 0.7 stops of light loss.
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Moderate warming when daylight and tungsten need to blend, especially for interview lighting, event rigs, and warmer skin tones.
Description
CTO-039 is a full-strength CTO with its 50 % crossover at 547 nm. The filter transitions sharply from low blue transmission (avg 33 %) into a high-throughput warm band: yellow averages 93.6 %, orange 91.2 %, and red 93.6 %, with a peak of 95.4 % at 632 nm. This places the transmission maximum in the orange-red sweet spot. Beyond 700 nm, the NIR rolls off to an average of 70.1 %, providing moderate infrared attenuation. The spectrum delivers a saturated, vivid warm tone concentrated in the yellow-through-red range.
Key Advantages
- Full CTO crossover at 547 nm with peak of 95.4 % at 632 nm - delivers maximum output in the orange-red region for a vivid warm conversion.
- Excellent warm-band uniformity (yellow, orange, red all > 91 %) - provides flat, even transmission across the entire warm visible range.
- Moderate NIR roll-off (avg 70 %) - reduces infrared heat load while maintaining good long-wavelength throughput.
- Hard-oxide durability - ion-assisted coating survives 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 - provides a vivid, saturated warm wash with excellent yellow-to-red uniformity for impactful scene design.
- Film colour correction - converts daylight fixtures to tungsten balance with a punchy, cinema-quality warm spectrum.
- Architectural and display lighting - transforms cool-white LEDs into rich warm-white sources for galleries, restaurants, and hospitality venues.
- Photography and creative filtration - delivers a strong warming filter effect with excellent colour saturation and low exposure compensation.
- Circadian lighting design - shapes evening lighting into a warm spectrum that supports natural sleep-wake cycles by suppressing blue content.
Need prototypes in days or production volumes next quarter? CTO-039 filters can be coated, diced, and shipped to your exact specifications
FAQ
CTO-039 FAQ
What is CTO-039 and what is it used for?
CTO-039 is a Color Temperature Orange Filter - Full CTO with Yellow-Red Passband (T50 % = 545 nm). CTO-039 is a full-strength CTO with its 50 % crossover at 547 nm. The filter transitions sharply from low blue transmission (avg 33 %) into a high-throughput warm band: yellow averages 93.6 %, orange 91.2 %, and red 93.6 %, with a peak of 95.4 % at 632 nm. Common uses include Stage and concert lighting, Film colour correction, Architectural and display lighting, and Photography and creative filtration.
What are the key optical specs of CTO-039?
Key published specs for CTO-039 include Colour shift direction: Warming (5600 K → 3800 K); Mired shift: +67 Mired; Correction strength: 1/2 CTO; Average transmittance: ~59.4 % T (visible range); Peak transmittance: ~95.4 % T near 632 nm.
What applications is CTO-039 best suited for?
CTO-039 is commonly used for Stage and concert lighting, Film colour correction, Architectural and display lighting, and Photography and creative filtration. Stage and concert lighting - provides a vivid, saturated warm wash with excellent yellow-to-red uniformity for impactful scene design.
Can CTO-039 be customized for size, substrate, or coating requirements?
KUPO lists the construction for CTO-039 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-039?
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
