CTO-037 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: ~60.5 % T (visible range)
- Peak transmittance: ~96.1 % T near 745 nm
- Minimum transmittance: ~0.8 % 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-037 delivers a +67 Mired shift to move 5600 K light toward 3800 K. Its smooth spectral slope creates a natural warming effect, with about 60.5 % 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-037 delivers a full-strength colour-temperature shift with its 50 % crossover at 550 nm and a striking spectral profile. UV is sharply blocked (T < 5 % from 380-392 nm), then transmission rises through the visible to reach a broad plateau above 85 % from 565-765 nm, peaking at 96.1 % at 745 nm. The yellow band averages 92.8 % and orange averages 90.6 %, placing maximum output squarely in the warm visible range. Notably, NIR rolls off to 41 % at 800 nm, limiting infrared heat transfer while maintaining excellent warm-visible throughput.
Key Advantages
- Full CTO conversion with 50 % crossover at 550 nm - delivers a complete daylight-to-tungsten colour shift.
- Broad high-transmission plateau (T > 85 % from 565-765 nm) - provides a wide, flat warm passband with excellent colour uniformity.
- NIR roll-off (41 % at 800 nm) - limits infrared heat transfer compared to standard longpass CTOs, protecting sensitive downstream optics and materials.
- Hard-oxide durability - ion-assisted coating resists 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 theatrical lighting - provides a clean full-CTO conversion with reduced infrared heat load, protecting gels and set materials.
- Film and broadcast colour correction - converts daylight sources to tungsten balance with a smooth, natural-looking warm spectrum.
- LED and lamp colour tuning - shapes cool-white LED output into a warm-white spectrum with controlled NIR to prevent detector saturation.
- Photographic warm filtration - delivers a strong warming effect for landscape and portrait photography with minimal NIR artefacts in digital sensors.
- Circadian and wellness lighting - shifts evening lighting toward warm yellow-orange to support natural melatonin cycles.
Need prototypes in days or production volumes next quarter? CTO-037 filters can be coated, diced, and shipped to your exact specifications.
FAQ
CTO-037 FAQ
What is CTO-037 and what is it used for?
CTO-037 is a Color Temperature Orange Filter - Full CTO with Peaked Warm Band (T50 % = 549 nm). CTO-037 delivers a full-strength colour-temperature shift with its 50 % crossover at 550 nm and a striking spectral profile. UV is sharply blocked (T < 5 % from 380-392 nm), then transmission rises through the visible to reach a broad plateau above 85 % from 565-765 nm, peaking at 96.1 % at 745 nm. Common uses include Stage and theatrical lighting, Film and broadcast colour correction, LED and lamp colour tuning, and Photographic warm filtration.
What are the key optical specs of CTO-037?
Key published specs for CTO-037 include Colour shift direction: Warming (5600 K → 3800 K); Mired shift: +67 Mired; Correction strength: 1/2 CTO; Average transmittance: ~60.5 % T (visible range); Peak transmittance: ~96.1 % T near 745 nm.
What applications is CTO-037 best suited for?
CTO-037 is commonly used for Stage and theatrical lighting, Film and broadcast colour correction, LED and lamp colour tuning, and Photographic warm filtration. Stage and theatrical lighting - provides a clean full-CTO conversion with reduced infrared heat load, protecting gels and set materials.
Can CTO-037 be customized for size, substrate, or coating requirements?
KUPO lists the construction for CTO-037 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-037?
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
