CTO-044 Color Temperature Orange (Warming) Filter
1/4 CTO colour-conversion filter shifting 5600 K toward 4500 K for seamless mixed-lighting balance in broadcast, film, and architectural applications.
- Colour shift direction: Warming (5600 K → 4500 K)
- Mired shift: +35 Mired
- Correction strength: 1/4 CTO
- Average transmittance: ~64.3 % T (visible range)
- Peak transmittance: ~94.8 % T near 644 nm
- Minimum transmittance: ~21.3 % T near 479 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-044 delivers a +35 Mired shift to move 5600 K light toward 4500 K. Its smooth spectral slope creates a natural warming effect, with about 64.3 % average visible transmittance and approximately 0.3 stops of light loss.
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Light warming for white-balance fine-tuning, subtle skin-tone warmth, and gentle golden-hour style looks.
Description
CTO-044 provides a half-strength CTO conversion with its 50 % crossover at 561 nm and excellent long-wavelength throughput. Transmission exceeds 85 % from 606-800 nm, peaking at 94.8 % at 644 nm. Red averages 92.6 % and NIR averages 89.3 %. A notable violet shoulder at 380 nm (83.1 %) gives this filter a secondary character: it suppresses green and blue (22.4 %) while preserving some short-wavelength content. The overall effect is a warm conversion with high output efficiency and a subtle violet warmth.
Key Advantages
- 50 % crossover at 561 nm with peak of 94.8 % at 644 nm - delivers half-CTO conversion with excellent efficiency in the warm bands.
- T > 85 % from 606-800 nm - provides a broad, flat high-transmission region covering the full orange-to-NIR range.
- Violet shoulder at 380 nm (83 %) - adds warmth complexity beyond standard CTO for richer colour character.
- Hard-oxide durability - ion-assisted coating resists 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 theatrical lighting - provides a standard half-CTO conversion with high output and a hint of warm-violet for scene enrichment.
- Film and broadcast colour correction - delivers efficient half-CTO conversion for blending daylight and tungsten sources on set.
- Architectural and hospitality lighting - shifts cool-white fixtures to warm-white with excellent output maintenance.
- Photography warm filtration - adds a natural golden warmth with minimal exposure compensation due to high peak transmission.
- Display and projection colour tuning - warms the output of cool LED sources while maintaining high brightness and colour consistency.
Need prototypes in days or production volumes next quarter? CTO-044 filters can be coated, diced, and shipped to your exact specifications.
FAQ
CTO-044 FAQ
What is CTO-044 and what is it used for?
CTO-044 is a Color Temperature Orange Filter - Half CTO with High Red-NIR (T50 % = 560 nm). CTO-044 provides a half-strength CTO conversion with its 50 % crossover at 561 nm and excellent long-wavelength throughput. Transmission exceeds 85 % from 606-800 nm, peaking at 94.8 % at 644 nm. Common uses include Stage and theatrical lighting, Film and broadcast colour correction, Architectural and hospitality lighting, and Photography warm filtration.
What are the key optical specs of CTO-044?
Key published specs for CTO-044 include Colour shift direction: Warming (5600 K → 4500 K); Mired shift: +35 Mired; Correction strength: 1/4 CTO; Average transmittance: ~64.3 % T (visible range); Peak transmittance: ~94.8 % T near 644 nm.
What applications is CTO-044 best suited for?
CTO-044 is commonly used for Stage and theatrical lighting, Film and broadcast colour correction, Architectural and hospitality lighting, and Photography warm filtration. Stage and theatrical lighting - provides a standard half-CTO conversion with high output and a hint of warm-violet for scene enrichment.
Can CTO-044 be customized for size, substrate, or coating requirements?
KUPO lists the construction for CTO-044 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-044?
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
