This chapter could be called “Practical Microscopy,” “The Microscope,” or simply “Microscopy,” but I chose to call it Köhler Illumination to emphasize the role of this essential—yet still not widely known more than a century after its introduction—technique of getting the best performance from a microscope. I have tried to provide in this chapter common, practical microscopy issues that don’t require a deep understanding of optical theory, ray diagrams, and the like. As will be seen, Köhler illumination provides a systematic approach to adjusting the illumination system without guessing how best to adjust the field diaphragm, substage condenser height, and opening of the substage condenser aperture diaphragm. In addition to optimizing optical resolution, Köhler illumination is fundamental to quality photomicrography and digital imaging.
KeywordsDust Uranium Retina Flare Smoke
- 1.Köhler A. Ein neues Beleuchtungsverfahren für microphotographische Zwecke [New method of illumination for photomicrographical purposes]. Z wiss Mikr. 1893;10(4):433–40. Original article available at http://www.archive.org/download/cbarchive_38379_1018934page433440einneuesbeleu1893/1018934page433440einneuesbeleu1893.pdf. Accessed 27 Feb 2012.
- 2.English translation available at http://books.google.com/books/download/Journal_of_the_Royal_Microscopical_Socie.pdf?id=0O4BAAAAYAAJ&output=pdf&sig=ACfU3U1DMogG4ZRyiuGdBqkVMWFzKWz6AQ. Accessed 27 Feb 2012.
- 3.Gill GW. Microscope cleaning tips, techniques and timing. LabMedicine. 2005;36(8):460.Google Scholar
- 4.Duke CV. Lens cleaning. Best practices review. Micros Today. 2004;12(2):42, 4.Google Scholar
- 5.Larson JM. Cleaning a microscope’s optical surfaces. Micros Today. 2001;10(4):27–8.Google Scholar
- 6.Gill GW. Köhler illumination. LabMedicine. 2005;36(9):550.Google Scholar
- 7.Haselmann H. Teaching microscopy. I. Microscopy as a field of teaching and research. Proc R Microsc Soc. 1967;2:337–43.Google Scholar
- 8.Haselmann H. Teaching microscopy. II. Didactic methods in teaching microscopy. Proc R Microsc Soc. 1967;2:344–55.Google Scholar
- 9.Gill GW. Care and feeding of microscopes: cleanliness is next to “goodliness.”. ASCT J Cytotechnol. 1997;1(2):73–5.Google Scholar
- 10.Bioindustrial Products. http://www.bioindustrialproducts.com/january_2012_catalog.pdf. Accessed 1 Mar 2012.
- 11.BD Biosciences. Cell culture flasks. http://www.bdbiosciences.com/cellculture/flasks/index.jsp. Accessed 1 Mar 2012.
- 12.Loveland RP. Photomicrography – a comprehensive treatise, vol. I. New York, NY: Wiley; 1970.Google Scholar