Patent ID: 8210678

Claim:
A multiband contrast enhancer comprising narrowband light-filtering means and sharp-cut light-filtering means, said multiband contrast enhancer providing: a) a maximum light transmittance for at least one wavelength within each of three wavelength ranges, the first wavelength range being from 490 nm to 510 nm, the second wavelength range being from 540 nm to 560 nm, the third wavelength range being from 620 nm to 720 nm, wherein the wavelengths of maximum light transmittance in each of the three wavelength ranges have a transmittance value which is at least 120 percent of the value of luminous transmittance of the multiband contrast enhancer; b) a minimum light transmittance for at least one wavelength within each of two wavelength ranges, the first wavelength range being from 515 nm to 530 nm, the second wavelength range being from 570 nm to 590 nm, wherein the wavelengths of minimum light transmittance in each of the wavelength ranges have a transmittance value less than 75 percent of the value of luminous transmittance of the multiband contrast enhancer; c) a light transmittance so that the value of the light transmittance at 400 nm is less than 50 percent of the value of the luminous transmittance of the multiband contrast enhancer; d) a light transmittance so that the value of the light transmittance at any wavelength from 200 nm up to a blocking wavelength is less than 1 percent, said blocking wavelength being between 380 nm and 460 nm; and e) wherein the light transmittance and luminous transmittance values of the multiband contrast enhancer are measured using CIE illuminant D65 in accordance with ANSI specification Z80.3-2001.