Patent ID: 8004764

Claim:
A method for color-compensated filtering of an optical beam, comprising the steps of: providing an illumination light source operable to produce the optical beam and direct the optical beam along an optical path; positioning an optical filter in the optical path such that the optical beam is incident on the optical filter, the optical filter being operable to receive the incident optical beam and produce an output light beam, wherein the optical filter comprises an optically effective material characterized by: a light transmittance of less than 1% for wavelengths below 420 nm; and a light transmittance for wavelengths complementary and near complementary to wavelengths below 420 nm that, combined with the transmittance for wavelengths below 420 nm, will result in the output light beam having a luminosity of about 90% and an excitation purity of 5% or less; and directing the output light beam onto a site to illuminate the site.