An imaging device includes print media and a plurality of ink jets for ejecting drops of substantially clear ink onto the print media. One of the print media and the substantially clear ink has a fluorescent characteristic and the other of the print media and the substantially clear ink is substantially non-fluorescent. The imaging device includes a fluorescence sensor having (i) a light emitter for illuminating the print media and the drops of substantially clear ink ejected onto the media by the plurality of ink jets with light of an activating wavelength, and (ii) a light detector for detecting a fluorescence intensity of light received from the print media and the drops of substantially clear ink ejected onto the media in an emission wavelength. A controller is configured to modify an operating parameter of the imaging device based on the fluorescence intensity detected by the sensor.