http://confocal-microscopy-list.275.s1.nabble.com/darkfield-references-tp7583371p7583378.html
Rheinberg! Funny... I think that that came from
some ancient literature ... I will have to search
condenser's maximum NA. The cone in the middle
excludes the components of smaller NAs. For this
objectives. However, because only a narrow band
coherent. Again, scattering theory rather than
through June 2015. Call us today for a free training evaluation.
>*****
>To join, leave or search the confocal microscopy listserv, go to:
>
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>Post images on
http://www.imgur.com and include the link in your posting.
>*****
>
>Jeff,
>
>concerning resolution, normal dark field is not any differfent from
>bright field, except maybe that Rayleigh may make more sense than Abbe,
>since you have a kind of self-luminous objects. In practical terms,
>resolution will be less since you have to cut down NA either from the
>objective or from the condenser. Concerning the smallest observable
>object, dark field is somewhat like fluorescence: Not the size is
>important, but the amount of light you can get out of it. If you want to
>dig deeper, the search term is ultramicroscopy, named so because it can
>visualize particles below the resolution limit. I estimate the term was
>en vogue from around 1900 to maybe the 1950ies.
>
>A 1902 experiment studied particles down to 4 nm, with sun light as
>light source, probably still the record for size: H. Siedentopf, R.
>Zsigmondy: Ãber Sichtbarmachung und GröÃenbestimmung
>ultramikroskopischer Teilchen, mit besonderer Anwendung auf
>Goldrubingläser. In: Annalen der Physik. 315, 1902, S. 139,,
>doi:10.1002/andp.19023150102
>
>Henry Siedentopf (Zeiss company) and Richard Zsigmondy also developed
>the initial version of the Slit-Ultramicroscope (Spaltultramikroskop),
>which uses an illumination principle much like todays light sheet
>fluorescence microscopes, to study colloids.
>
>There are two Nobels associated with the technique.
>Ultramicroscopy was used in the Millikan-Experiment
>(
https://en.wikipedia.org/wiki/Oil_drop_experiment) which was rewarded
>with the physics Nobel in 1923.
>And in 1925 Zsigmondy got the Chemistry Nobel for his colloid studies.
>His Nobel Lecture is online
>(
http://nobelprize.org/nobel_prizes/chemistry/laureates/1925/zsigmondy-lecture.pdf)
>
>Dark field seems to be particularly useful in visualizing living
>Spirochaete bacteria, thus the technique boomed from 1906 when the
>Syphilis bacteria where discovered.
>
>Concerning Rheinberg Illumination that Barbara mentioned, that was
>developed actually a little later than she thought: Julius Rheinberg of
>London first described it in 1896 (according to one source). In
>professional microscopy it seems to have been replaced mostly by phase
>contrast. But Hobbyists still use it to make beautiful images.
>
>If you should learn German anyway to read the Siedentopf & Zsigmondy
>paper (don't know if there is a translated version somewhere), you also
>can have a look at the German Wikipedia article on
>Dunkelfeldmikroskopie, which I think is quite good. But then, I may not
>be entirely impartial on that particular subject :-)
>
>Cheers
>Steffen
>
>
>Am 30.01.2015 um 23:44 schrieb Jeff Spector:
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> >
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy> > Post images on
http://www.imgur.com and include the link in your posting.
> > *****
> >
> > Greetings,
> > Can someone please point me to some references involving the theory
> > behind darkfield microscopy? I understand the basic idea, but all I can
> > find are different iterations of the basic idea that you block most of the
> > light and only image scattered light. I'd like to learn a bit more about
> > technical aspects of darkfield, i.e. what is the smallest object you can
> > observe? What role do illumination power and camera exposure play in the
> > quality of the final image. What role does specimen thickness/size play in
> > the final image and can you discern objects of different size
> > etc...
> > Any help would be greatly appreciated. Perhaps I simply need to read up on
> > scattering theory?
> > thanks..
> > -jeff
> >
> >
> > --
> > ------------------------------------------------------------
> > Steffen Dietzel, PD Dr. rer. nat
> > Ludwig-Maximilians-Universität München
> > Walter-Brendel-Zentrum für experimentelle Medizin (WBex)
> > Head of light microscopy
> >
> > Marchioninistr. 27
> > D-81377 München
> > Germany