My living room has one of those 'light tree'-type floor lamps, and I was thinking of putting a couple of gels into its top two light fixtures, to combat the painful achromaticity of the room.    From Wordnik.com.  [Peter Rogers's Blog] Reference

More information: A biological quarter-wave retarder with excellent achromaticity in the visible wavelength region by NW Roberts, T-H Chiou, NJ Marshall and TW Cronin.    From Wordnik.com.  [PhysOrg.com - latest science and technology news stories] Reference