Such females are tetrachromats, since they require a mixture of four spectral lights to match an arbitrary light.

The spectral light from my amulet showed me Billy's strained face first, and then the area immediately around us.

This time the splash of spectral light was an intense, electric, sapphire blue.

Beyond the temple the trees of the forest shimmered in the spectral light.

When the moon was clear of the clouds the mountain glowed with a strange, spectral light.

An ice-field on the far horizon is moving slowly southward in the spectral light.

My hands looked grey in the spectral light.

The spectral gray light which rose from the tracks they left behind looked like vapor rising from dry ice.

Dichromats can match any color they see with a mixture of no more than two pure spectral lights.

Everything she saw glowed with a spectral light, as if Shadow's Gate was no longer wholly of this world.