Thin-section photomicrography
A fundamental problem in conventional light microscopy has long been the lack of image quality brought about by the use of sections which are thicker than the depth of field (DOF) of the microscope. These sections are used because “paraffin & steel” microtomy techniques preclude sections thinner than a few microns. The transmission electron microscope, however, requires section thicknesses of less than a micron. This requirement has resulted in the development of “epoxy & glass” microtomy techniques, and the ability to cut sections as thin as a few hundred Ångstroms. These thin sections are not routinely used for light microscopy because of the difficulty of preparation, the need for large section areas, and because of photomicrographic problems. The first two reasons may inhibit the use of thin sections in some situations, but the photomicrographic problems are surmountable.There is some disagreement in the literature regarding the actual DOF in photomicrographic situations.