Beyond brightfield: “forgotten” microscopic modalities

Abstract

“Forgotten” microscopic modalities, devices, and accessories derived from or complementary to brightfield microscopy are briefly surveyed. These include off­axis illumination, schlieren contrast, Abbe diffraction apparatus, Rheinberg illumination, darkfield and phase-contrast microscopy combined, incident-illumination microscopy, camera lucida, and comparison microscopy. Examples of their use are shown. While most of them are no longer or only rarely available or used, they are still important for proper understanding of image formation, contrast generation, and data interpretation in microscopy. In some cases, they are superior to their more modern counterparts.