Chapter 9 327 The gluing together and darkening of fibers is also measured by taking a photograph along the axis of the mounting cylinder. A plot of luminosity versus distance is obtained by scanning the image circumferentially along the middle of the eyelash assembly (see Figure 14). From the plot of luminosity versus distance we found that the number of peaks decreased as a result of mascara treatment. Specifically, the number of peaks per unit area was 10.94 peaks/mm and 5.94 peaks/mm for untreated and mascara treated eyelashes, respectively. Equally interesting, the fibers became darker as a result of the treatment. When comparing Figures 14b and 14c, the peak Figure 13. View of (a) untreated and (b) mascara-treated eyelashes mounted on a Teflon cylinder looking down the axis of the cylinder. Cropped sections of images of (c) untreated and (d) mascara-treated eyelashes are also shown and correspond to the photographs in (a) and (b), respectively. Fourier transform plots, (e) and (f), were generated for the cropped images in (c) and (d), respectively.