Patent ID: 8107696

Claim:
A fluorescence standard for identifying variations in illumination by a light source emitting light in the approximate wavelength range of 375 nm to 430 nm during imaging of the facial skin of a person with a camera conducted at a plurality of times, comprising: a fluorescent standard, which fluoresces in response to light in the approximate wavelength range of 375 nm to 430 nm, said fluorescent standard having two areas with different fluorescent response, a first area formed from a filter glass of a first type in a first layer and having a fluorescent response to light in the approximate wavelength range of 375 nm to 430 nm and a second area formed from a filter glass of a second type in a second layer partially covering said first layer and attenuating the fluorescent response of said first layer in the area of overlap, a holder for holding said standard near the facial skin of the person in a substantially reproducible spacial relationship between said camera, said standard and said facial skin, permitting said standard and the facial skin of the person to be similarly and simultaneously illuminated by the light in the approximate wavelength range of 375 nm to 430 nm and to be photographed by said camera at each of the plurality of times of imaging.