LEE211 Neutral Density (ND) Filter
0.7-OD neutral-density glass: a flat 5–7 % T from 380–780 nm—LEE 211 gel punch in a heat-proof optic for true gray, three-stop dimming.
- Blue end: ≈ 6 % T @ 380 nm (spectrally flat)
- Red end: ≈ 6 % T @ 780 nm (±0.5 % ripple)
- Optical density: 1.11 – 1.14 OD (≈ 3-stop cut)
- Colour shift: < ±1 % relative RGB variation
- Construction: Ion-assisted hard-oxide; 5 – 450 mm, 0.21 – 3.8 mm thick
- Custom options: AOI tuning, edge finishing, rapid prototypes
Learn more
LEE211-glass is KUPO’s true neutral-density attenuator that mirrors the stage-lighting gel
“LEE 211 Full ND” while offering the endurance of an all-glass, hard-oxide optic. Transmission
sits between 5 % and 7 % across the entire 380 – 780 nm span, with ripple held to roughly
±0.5 %. The result is an optical density around 1.1 OD—about a three-stop reduction—with
no perceptible hue bias. Whites stay white, saturated colours remain accurate, and beam
quality is preserved thanks to a low-scatter dielectric stack on polished glass.
KUPO can coat Borofloat®, soda-lime, Schott D263 T, or Corning Eagle XG glass cut to any
outline—from 5 mm chips to 450 mm plates—in thicknesses of 0.21 – 3.8 mm, and ship
prototypes in roughly two weeks.
Typical uses: precise exposure control in imaging, heat-proof dimming for stage or
architectural fixtures, projector and display calibration, predictable attenuation on laser
benches, and flat-field intensity reduction in spectroscopy or fluorescence setups.
Description
LEE211 is a true neutral-density (ND) glass filter that mimics the stage-lighting gel “LEE 211 Full ND.” It passes only about 5 – 7.5 % of incident light right across the entire 380 – 780 nm range, with ripple held to roughly ±0.5 %. Because the curve is essentially flat, the filter trims intensity without introducing any discernible colour bias, making it a reliable “gray” attenuator for cameras, luminaires, projectors, and lab light sources.
Key advantages
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Uniform 5 – 7.5 % transmission – smooth, nearly wavelength-independent attenuation for predictable exposure control.
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Neutral colour balance – < 1 % variation in relative RGB response keeps whites white and saturated colours accurate.
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Broad spectral reach (UV-visible-NIR) – consistent performance from 380 nm through at least 780 nm simplifies mixed-sensor or mixed-lamp setups.
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Low scatter, low ripple – dielectric stack and polished glass preserve beam quality and MTF.
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Production-scale formats – cut to any round, square, or free-form shape (5 – 450 mm), 0.21 – 3.8 mm thick, on Borofloat®, soda-lime, D263 T, or Eagle XG substrates.
Typical applications
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Imaging exposure control – tame high-intensity flash, LED, or laser illumination without stopping down lenses.
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Stage & architectural lighting – swap fragile gels for hard-coated glass ND when fixtures run hot or duty cycles are long.
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Projector and display calibration – reduce output for photometric measurements without skewing colour temperature.
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Spectroscopy & photometry – attenuate reference beams while maintaining a flat baseline for accurate absorbance readings.
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Security & traffic cameras – keep daylight levels in the sweet spot for wide-dynamic-range sensors.
Need prototype pieces tomorrow or thousands of parts next month? LEE211 equivalents can be coated, diced, and delivered on your schedule.
