Abstract: The response of a fluorescence detector is calibrated using apparatus and methods for both static and dynamic calibrations. The apparatus and methods are especially suited for portable use in field calibration of fluorescence detectors of authentication systems that use non-visible light. The calibration apparatus incorporates standard target elements (20) comprising predetermined fluorescent substances with known emission spectra, and either non-fluorescent substances or fluorescent substances with other known emission spectra. The substances are either mixed in predetermined proportions, or one substance is arranged in a predetermined pattern (170), such as a bar code, on the other substances. An aperture (30) exposes a predetermined surface area of a standard target element to the view of the fluorescence detector. The distance of the standard target element from the optical front end (70) of the fluorescence detector to be calibrated is adjustable (50).