CRI-31 is a colour-rendering improvement (CRI) filter that warms and smooths spiky LED/HMI spectra by trimming deep blue and yellow-green while preserving cyan/blue-green and long-red. Transmission rises to ~55% near ~410 nm, dips into a blue notch around ~430–435 nm (~20–25% T), climbs to a high blue-cyan passband of ~94–96% T across ~460–520 nm, falls to ~45–50% near ~570–590 nm, then recovers to ~94–96% T from ~640–700 nm before tapering to ~48–52% by ~780 nm.
Key advantages
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Raise CRI/TLCI and R9 — moderates the ~430 nm spike and the ~570–590 nm region while keeping strong long-red for natural skin, wood, food, and fabrics.
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Dual-pass profile — high throughput in blue-cyan (~460–520 nm) and long-red (~640–700 nm) with controlled attenuation at ~430 nm and ~570–590 nm.
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Colour-temperature tuning — shifts overly cool sources toward neutral/warm without introducing magenta/green casts.
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Predictable shaping — smooth slopes and broad features avoid banding and preserve colour balance.
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Built for production — durable dielectric stack for sets, stages, and architectural fixtures; optional rear-surface AR and slight wedge to suppress ghosts.
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Custom formats — Borofloat®, Eagle XG, or D263 T (0.21–3.8 mm) for high-temp duty to ~450 °C; soda-lime for ≤150 °C. Sizes 5–450 mm.
Typical applications
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Cinema/TV lighting — lift TLCI/CRI and skin-tone accuracy with less in-camera correction.
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Photography & events — warmer, more flattering faces and textiles under LED or HMI.
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Retail, museum & hospitality — reduce green cast and reveal natural reds in merchandise and art.
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Architectural & display — refine off-the-shelf luminaires for premium colour.
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Machine vision — balance channels when red features matter and green/blue glare is problematic.
Need test chips tomorrow or thousands next quarter? CRI-31 filters are coated and cut-to-size (including dicing) to your exact spec—fast.
