
(a) (b)
FIGURE 24.9 Bright-eld (a) versus dark-eld (b) images obtained from a stained object. Dark-eld images enhance highly diractive features,
such as cell wall boundaries, that are comprised of strong refractive index variations between the feature and its surround. By comparison, bright-
eld image contrast is produced by variations in absorption of colored dyes or natural pigments that oen ll the entire cell, making the cell wall
or any internal structures less apparent. Arrows point to a spore that exemplies the dierence between these two microscope congurations. In
the dark-eld image, the cell wall is more clearly delineated ...