CRI-21 is a colour-rendering improvement (CRI) filter that warms and smooths spiky LED/HMI spectra by reducing deep blue and broad yellow-green while preserving a cyan window and strong long-red. Transmission is high (~88–92% at ~390–430 nm), drops to ~25–30% near ~450–455 nm, rebounds to ~88–92% around ~480–500 nm, then dips across ~520–600 nm to ~33–36% near ~560–580 nm. It rises steeply to ~93–95% by ~660–720 nm and holds ~91–93% toward ~780 nm.
Key advantages
-
Raise CRI/TLCI and R9 — moderates the ~450 nm spike and the ~520–600 nm band while keeping strong long-red for natural skin, wood, food, and fabrics.
-
Dual-pass profile — high throughput in blue-cyan (~480–500 nm) and long-red (>~660 nm) with controlled attenuation at ~450 nm and ~560–580 nm.
-
Colour-temperature tuning — shifts overly cool sources toward neutral/warm without magenta/green casts.
-
Predictable shaping — smooth slopes and broad features avoid banding and preserve colour balance.
-
Built for production — durable dielectric stack for sets, stages, and architectural fixtures; optional rear-surface AR and slight wedge to suppress ghosts.
-
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
-
Cinema/TV lighting — lift TLCI/CRI and skin-tone accuracy with less in-camera correction.
-
Photography & events — warmer, more flattering faces and textiles under LED or HMI.
-
Retail, museum & hospitality — reduce green cast and reveal natural reds in merchandise and art.
-
Architectural & display — refine off-the-shelf luminaires for premium colour.
-
Machine vision — balance channels where red features matter and blue/green glare is problematic.
Need test chips tomorrow or thousands next quarter? CRI-21 filters are coated and cut-to-size (including dicing) to your exact spec—fast.
