Efficacy of a color conversion filter in color-vision testing

C Daylight(TM) glasses are designed to convert light from domestic incandes cent lamps (approximate to Illuminant A) to the Illuminant C phase of dayli ght. The efJicacy of this conversion is quantified here far the Farnsworth D15 test. Spectral transmittance and reflectance data for the filter and D1 5 caps, respectively, are used to compute chromaticities of the caps under illuminants C, A, and the filtered illuminant SA. The chromaticities of A a nd fA deviate from C by 13 JNDs and 1.6 JNDs, respectively and, similarly d isparate shifts occur for the 15 caps. After allowing for von Kries adaptat ion, the chromatic spacing between some adjacent caps approaches I JND for Illuminant A, but is less than 0.1 JND for fA, It is concluded that the col or conversion is efficient, (C) 2000 John Wiley & Sons, Inc.