CRI-18 Color Rendering Improvement Filter

CRI-18 is a colour-rendering improvement (CRI) filter that warms and smooths spiky LED/HMI spectra by trimming deep blue and yellow-green while preserving blue-cyan and long-red. Transmission shows two blue notches — ~15% T near ~400–405 nm and ~12–15% T around ~445–455 nm — followed by a blue-cyan pass of ~90–92% T at ~495–510 nm. It then dips to ~24–27% T across ~545–560 nm before climbing to a long-red plateau of ~93–95% T from ~630–710 nm, easing to ~62–65% by ~780 nm.

Key advantages

• Raise CRI/TLCI and R9 — moderates ~400–455 nm and ~545–560 nm while keeping strong long-red for natural skin, wood, food, and fabrics.

• Twin-notch, dual-pass profile — deep control in blue with high throughput in blue-cyan (~495–510 nm) and long-red (~630–710 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-18 filters are coated and cut-to-size (including dicing) to your exact spec—fast.