ABSTRACT
Various techniques of light microscopy have been employed to observe biofilms (Lawrence et al., 1991; Keevil and Walker, 1992; Walker and Keevil, 1994 and references therein). Light microscopy uses glass lenses to bend and focus light rays in order to produce enlarged images of small subjects, such as bacterial cells. The resolution
of a light microscope is determined by the numerical aperture of its lens system and by the wavelength of the light it employs, which in the case of a conventional light source is of the order of about 0.2 µm. The most common types of light microscopes are the bright-field-, dark-field-, phase-contrast-, and fluorescence microscopes. Each yields a distinctive image and may be used to observe different aspects of microbial morphology.
