CRI-9 is a colour-rendering improvement (CRI) filter that warms and smooths spiky LED/HMI spectra by trimming deep blue and broad yellow-green while preserving a clean cyan pass and strong long-red. Transmission starts high (~88–92% from ~390–420 nm), drops to a deep notch of ~6–10% near ~445–455 nm, rebounds to ~78–82% around ~495–505 nm, then dips across ~520–600 nm to ~14–18% near ~550–560 nm. From ~640 nm it climbs quickly to ~92–95% through ~680–750 nm and finishes near ~90% by ~780 nm.
Key advantages
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Raise CRI/TLCI and R9 — moderates the ~450 nm spike and the ~520–600 nm band while keeping long-red energy for natural skin, wood, food, and fabrics.
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Blue-notch with green trough — deep attenuation at ~445–455 nm plus a broad ~520–600 nm reduction, with high throughput in cyan (~495–505 nm) and long-red (>~640 nm).
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High long-red throughput — about 92–95% T from ~680–750 nm supports rich reds and flattering skin tones.
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Predictable shaping — smooth slopes and broad features avoid banding and keep colour moves consistent.
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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 where red features matter and blue/green glare is problematic.
Need test chips tomorrow or thousands next quarter? CRI-9 filters are coated and cut-to-size (including dicing) to your exact spec—fast.
