CTO-002 Color Correction Filter
½-CTO glass filter: trims blue (25 % @ 400 nm → 19 % @ 450 nm) then rises smoothly to ~88 % at 630 nm, pulling 5600 K sources down ≈1500 K without big lumen loss.
- Blue region: 25 % T @ 400 nm • 19 % T @ 450 nm
- 50 % point: ~550 nm (mid-slope transition)
- Red throughput: > 80 % T above 600 nm (peak ~88 % T @ 630 nm)
- CCT shift: −1500 K (≈ ½-CTO)
- Construction: Ion-assisted hard-oxide; 5 – 450 mm, 0.21 – 3.8 mm thick
- Custom options: Ripple flattening, AOI tuning, rapid prototypes
Learn more
CTO-002 gives a moderate “warm-amber” push—about a ½-CTO step—
dropping cool-white LEDs or daylight HMIs roughly 1500 K toward a tungsten look.
Transmittance starts at ~25 % around 400 nm, holds ~19 % near 450 nm, then climbs
smoothly, crossing 50 % close to 550 nm and peaking near 88 % at 630 nm before a
gentle taper through the far red. The balanced slope trims excess blue but leaves
enough green that colours stay natural, not cyan-shifted.
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 can ship prototypes in roughly two weeks.
Typical uses: warming daylight fixtures on set, softening LED house lights,
subtle strobe modifiers, museum CCT tweaks, and machine-vision systems that need a
blue lift without heavy attenuation.
Description
CTO-002 is a medium-strength “warm-amber” correction filter—about a ½-CTO step—for dialing cool-white LEDs or daylight fixtures down toward a tungsten look without sacrificing too much output. It transmits roughly 25 % at 400 nm, sits near 19 % around 450 nm, then climbs smoothly: crossing 50 % by ~ 550 nm and peaking close to 88 % near 630 nm before tapering through the far red. The gradual rise trims excess blue, lifts amber–red energy, and typically shifts a 5600 K source to the 4000 – 4300 K range—warm enough to match practical lamps while keeping skin tones natural.
Key advantages
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Moderate ½-CTO shift – Drops CCT by ~1500 K, perfect for mixing daylight heads with tungsten fills.
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High red throughput – > 80 % above 600 nm preserves brightness and renders warm colours accurately.
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Smooth blue cut – No sharp notches, so spectra stay camera-friendly without green spikes.
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Heat-resistant oxide coating – Handles high-power HMIs, LEDs, and xenon follow-spots far beyond the limits of plastic gels.
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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 or HMIs so they grade smoothly with tungsten practicals.
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Stage & architectural rigs – Soften cool LED house lights for intimate amber ambience without gel swaps.
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Photography modifiers – Bring strobes closer to incandescent colour without stacking multiple sheets.
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Museum & retail displays – Enhance warmth in exhibits while keeping UV well below conservation limits.
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Machine-vision lighting – Boost red-channel contrast for inspecting organic materials or heat-printed codes.
Need a prototype in days or production volume next month? CTO-002 filters can be coated, cut, and shipped to your exact specification—fast.
