CTO-027 Color Temperature Orange (Warming) Filter
3/4 CTO colour-conversion filter shifting 5600 K toward 3400 K for seamless mixed-lighting balance in broadcast, film, and architectural applications.
- Colour shift direction: Warming (5600 K → 3400 K)
- Mired shift: +100 Mired
- Correction strength: 3/4 CTO
- Average transmittance: ~50.6 % T (visible range)
- Peak transmittance: ~93.3 % T near 780 nm
- Minimum transmittance: ~10.6 % T near 437 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-027 delivers a +100 Mired shift to move 5600 K light toward 3400 K. Its smooth spectral slope creates a natural warming effect, with about 50.6 % average visible transmittance and a low amount of light loss.
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Strong but not full warming when you want a natural blend between daylight and tungsten sources.
Description
CTO-027 produces a strong warm shift with its 50 % crossover at 621 nm, deep in the orange-red transition zone. Blue and green wavelengths are heavily suppressed (blue avg 14.7 %, green avg 25.5 %), while red transmission climbs to an average of 74.1 % and NIR reaches 92.2 %, peaking at 93.5 % at 797 nm. A moderate violet shoulder (380 nm at 62 %) adds spectral character. The profile delivers a firmly red-dominant output suited to strong warm-colour applications where blue-green content must be minimised.
Key Advantages
- 50 % crossover at 621 nm - places the transition firmly in the orange-red region for a strong colour-temperature shift.
- High NIR throughput averaging 92.2 % - maintains excellent efficiency in the near-infrared band for combined visible-red and NIR applications.
- Strong blue-green suppression - reduces cool-tone content to below 26 %, ensuring a warm, red-biased output.
- 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 event lighting - creates strong amber-to-red washes for campfire, lava, and warm sunset scenes from daylight fixtures.
- Film colour correction - provides a heavy daylight-to-tungsten conversion for matching warm practical lighting on set.
- Architectural and landscape lighting - transforms neutral LED sources into warm red accent lights for facade and garden illumination.
- Machine vision with red-NIR emphasis - passes red and NIR illumination bands while rejecting blue-green for high-contrast defect detection.
- Agricultural and horticultural lighting - shapes broadband sources to emphasise red and far-red wavelengths beneficial for flowering and fruiting.
Need prototypes in days or production volumes next quarter? CTO-027 filters can be coated, diced, and shipped to your exact specifications.
FAQ
CTO-027 FAQ
What is CTO-027 and what is it used for?
CTO-027 is a Color Temperature Orange Filter - Strong Red Shift (T50 % = 620 nm). CTO-027 produces a strong warm shift with its 50 % crossover at 621 nm, deep in the orange-red transition zone. Blue and green wavelengths are heavily suppressed (blue avg 14.7 %, green avg 25.5 %), while red transmission climbs to an average of 74.1 % and NIR reaches 92.2 %, peaking at 93.5 % at 797 nm. Common uses include Stage and event lighting, Film colour correction, Architectural and landscape lighting, and Machine vision with red-NIR emphasis.
What are the key optical specs of CTO-027?
Key published specs for CTO-027 include Colour shift direction: Warming (5600 K → 3400 K); Mired shift: +100 Mired; Correction strength: 3/4 CTO; Average transmittance: ~50.6 % T (visible range); Peak transmittance: ~93.3 % T near 780 nm.
What applications is CTO-027 best suited for?
CTO-027 is commonly used for Stage and event lighting, Film colour correction, Architectural and landscape lighting, and Machine vision with red-NIR emphasis. Stage and event lighting - creates strong amber-to-red washes for campfire, lava, and warm sunset scenes from daylight fixtures.
Can CTO-027 be customized for size, substrate, or coating requirements?
KUPO lists the construction for CTO-027 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-027?
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
