CTO-008 Color Correction Filter
⅜-CTO glass filter: trims blue to ≈ 18 % at 450 nm, peaks near 90 % above 685 nm, and nudges daylight sources ~1200 K warmer without heavy output loss.
- Blue region: ≈ 18 % T @ 450 nm • 40 % T @ 540 nm
- Amber ramp: 70 % T @ 600 nm → > 90 % T > 685 nm
- CCT shift: –1200 K (≈ ⅜-CTO)
- Red plateau: ≥ 85 % T beyond 650 nm (bright skin tones)
- Construction: Ion-assisted hard-oxide; 5–450 mm, 0.21–3.8 mm thick
- Custom options: AOI tuning, ripple flattening, rapid prototypes
Learn more
CTO-008 applies a strong amber bias—roughly a ⅜-CTO step—ideal for nudging
daylight or cool-white sources toward a tungsten feel without stealing too much punch.
Transmittance is only ~18 % at 450 nm, rises smoothly to ~40 % at 540 nm, 70 % by 600 nm,
and levels near 90 % above 685 nm before tapering through the far red. The gentle slope
trims blue/green just enough to bring a 5600 K fixture down to ≈ 4300–4500 K, keeping
skin tones warm and output high.
KUPO coats Borofloat®, soda-lime, Schott D263 T, or Corning Eagle XG substrates cut to any
outline—from 5 mm chips to 450 mm plates—with thicknesses of 0.21–3.8 mm, and ships
prototypes in roughly two weeks.
Typical uses: warming daylight panels on film sets, softening cool LED house
lights, subtle flash modifiers, cosy museum/retail lighting, and red-contrast machine-vision
tasks.
Description
CTO-008 adds a pronounced amber bias—roughly a ⅜-CTO step—ideal when daylight or cool-white sources need a noticeable, but not full-tungsten, warm-up. The coating lets only about 18 % of blue (~450 nm) through, then climbs steadily: ~40 % at 540 nm, 70 % at 600 nm, and levels near 90 % beyond 685 nm.
That smooth tilt trims excess blue/green, boosts amber-red energy, and typically shifts a 5600 K fixture down to the 4300–4500 K range—warm enough for flattering skin tones while preserving most of the output.
Key advantages
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Mid-strength ⅜-CTO correction – Lowers CCT by ~1200 K, perfect for blending daylight heads with warmer fills.
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High red throughput – ≥ 85 % above 650 nm keeps brightness high and colours rich.
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Gentle spectral slope – No sharp notches, so cameras see a neutral spectrum without green spikes.
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Heat-stable oxide stack – Survives high-power LEDs, HMIs, and tungsten halogens far beyond plastic-gel limits.
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Custom formats – Round, square, or free-form blanks from 5 mm to 450 mm, 0.21–3.8 mm thick, on Borofloat®, soda-lime, Schott D263 T, or Corning Eagle XG glass.
Typical applications
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Film & broadcast lighting – Warm daylight panels just enough to grade smoothly with tungsten practicals.
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Stage & architectural rigs – Soften cool LED house lights for inviting ambience without deep-orange gels.
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Photography modifiers – Fine-tune strobes in mixed-light setups while retaining punch.
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Museum & retail displays – Add warmth to LED spotlights while keeping UV extremely low.
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Machine-vision illumination – Boost red-channel contrast for inspecting organic materials or heat-printed codes.
Need prototypes in days or production lots next quarter? CTO-008 filters can be coated, cut, and shipped to your exact specification—fast.
