CTO-040 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: ~63.5 % T (visible range)
- Peak transmittance: ~95.8 % T near 606 nm
- Minimum transmittance: ~2.6 % 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-040 delivers a +35 Mired shift to move 5600 K light toward 4500 K. Its smooth spectral slope creates a natural warming effect, with about 63.5 % 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-040 presents a distinctive spectral profile: a violet shoulder (380-430 nm at avg 54 %) drops into a deep blue notch (T < 5 % from 454-509 nm) before rising through a clean warm transition to 50 % at 552 nm and reaching > 85 % from 570-800 nm. Orange peaks at 95.4 % and the red band averages 91.7 %. The blue notch effectively removes the 450-510 nm band while preserving violet and warm wavelengths, creating a warm output with a subtle magenta undertone rather than a standard amber character.
Key Advantages
- Deep blue notch (T < 5 % from 454-509 nm) - precisely removes the blue band while preserving violet and warm wavelengths for unique colour character.
- High warm-band transmission (orange peak 95.4 %, red avg 91.7 %) - maintains excellent output efficiency in the warm spectrum.
- Magenta-warm tonality - the retained violet combined with strong warm tones creates a richer, more complex colour than standard CTO.
- 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 effects - creates a warm wash with a distinctive violet-pink undertone for romantic, twilight, or fantasy scenes.
- Film and photography creative filtration - produces a non-standard warm tone that adds visual interest to skin tones and golden-hour scenes.
- Blue-LED suppression - specifically removes the 450-510 nm peak from white LED sources while preserving other colours for improved circadian comfort.
- Display colour correction - compensates for blue-heavy LED displays by notching out peak blue emission while maintaining warm colour fidelity.
- Machine vision selective filtering - blocks the blue band while passing violet and warm wavelengths for multi-channel inspection under specific illumination.
Need prototypes in days or production volumes next quarter? CTO-040 filters can be coated, diced, and shipped to your exact specifications.
FAQ
CTO-040 FAQ
What is CTO-040 and what is it used for?
CTO-040 is a Color Temperature Orange Filter - Blue-Notch CTO (T50 % = 553 nm). CTO-040 presents a distinctive spectral profile: a violet shoulder (380-430 nm at avg 54 %) drops into a deep blue notch (T < 5 % from 454-509 nm) before rising through a clean warm transition to 50 % at 552 nm and reaching > 85 % from 570-800 nm. Orange peaks at 95.4 % and the red band averages 91.7 %. Common uses include Stage and theatrical lighting effects, Film and photography creative filtration, Blue-LED suppression, and Display colour correction.
What are the key optical specs of CTO-040?
Key published specs for CTO-040 include Colour shift direction: Warming (5600 K → 4500 K); Mired shift: +35 Mired; Correction strength: 1/4 CTO; Average transmittance: ~63.5 % T (visible range); Peak transmittance: ~95.8 % T near 606 nm.
What applications is CTO-040 best suited for?
CTO-040 is commonly used for Stage and theatrical lighting effects, Film and photography creative filtration, Blue-LED suppression, and Display colour correction. Stage and theatrical lighting effects - creates a warm wash with a distinctive violet-pink undertone for romantic, twilight, or fantasy scenes.
Can CTO-040 be customized for size, substrate, or coating requirements?
KUPO lists the construction for CTO-040 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-040?
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
