Photo-aging monitoring of light-based chemical indicators that experience performance degradation as the cumulative amount of light exposure from measurement and/or reference illumination increases from usage. Differing regions on a chemical indicator are illuminated with measurement illumination light of differing exposures, for example, higher brightness, longer exposure times, or both. Readings from the differing regions are compared with known aging information for the chemical indicator at issue to determine a confidence factor for the measurements. The confidence factor can be used to control various actions relating to measurements acquired from the chemical indicators, such as compensating measurement readings for photo-aging, assigning confidence levels to measurement readings, and issuing alerts to users when photo-aging exceeds one or more predetermined thresholds.
