Figure 2.

Confocal microscopy images of dried matchsticks. The fluorescence signal is overlaid in red on grayscale reflection images. The only appreciable fluorescence signal was found in the matchstick heads. Scale bar for part a is 500 nm.

Confocal microscopy images of dried matchsticks. The fluorescence signal is overlaid in red on grayscale reflection images. The only appreciable fluorescence signal was found in the matchstick heads. Scale bar for part a is 500 nm.