1The artist's use of chiaroscuro created an imperceptibly subtle gradient of light and shadow in the painting.
2As the disease progressed, her symptoms changed imperceptibly at first, but eventually became more pronounced.
3The imperceptibly slow movement of the glacier was only visible through time-lapse photography.
4The company's financial troubles began imperceptibly, with a slight decline in sales that was initially dismissed as a minor fluctuation.
5The imperceptibly small variations in the data were only detectable through advanced statistical analysis.