A clear lens lying flat under a lamp, its surface showing only a faint violet-green reflection glint.

Coatings and filters

Residual reflection

Optical glossaryCoatings and filters

The faint color an AR coating still reflects — green, gold or blue depending on the layer design. A signature, not a flaw.

A bare surface reflects evenly across the colors. An anti-reflective coating pushes reflection far down in the middle of the spectrum and leaves a little at one end — the color you see. The curve is illustrative, not a CLIFF coating's measurement.

Illustrative · the shape of the principle, not measured data

In more depth

An anti-reflective stack cannot cancel every color equally. Designers push reflection lowest in the middle of the visible spectrum, where the eye is most sensitive, and let a little remain toward one end — which is the faint green, gold or blue sheen you see when a coated lens catches the light.

The color is a signature of the layer design, not a sign of wear or a fault, and it looks the same from lens to lens of the same coating. A patchy or uneven sheen, on the other hand, can mean damage or contamination on the surface.

Related terms

Anti-reflective (AR) coatingMicroscopic layers tuned so surface reflections cancel. More light through the lens, no bright rectangles over your eyes, no headlight starbursts.Hard coatingA hardened protective layer that resists scratching. The foundation every other coating is built on.Blue light filteringAttenuation of the blue end of the visible spectrum, associated with reduced eye fatigue on long screen days. The evidence supports comfort, not medical protection.

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