MicrobeHunter.com Microscopy Forum

Here is the chart I referenced in this thread: viewtopic.php?f=6&t=5026&p=45736#p45736

I don't have a scanner, and I am unlikely to do it at the library in the near future so I made a couple of photographs that cover it.

It's a little difficult to read. Perhaps , if I change the format to 3:2 , and use 3 panels it will be a little sharper.



There, that's better.

Thank you for sharing.

So for small protozoa, bright contrast high is "generally preferred", while dark contrast medium "may reveal additional details".

B Minus seems to be used mostly for stained slides, glass like internal inclusions and some blood work.

Thanks for posting!.. Looks like a goldmine of info.....

BillT

zzffnn wrote:Thank you for sharing.

So for small protozoa, bright contrast high is "generally preferred", while dark contrast medium "may reveal additional details".

Generally it seems , yes. Probably depends a little on the species and the medium too. Adding glycerin or other to the medium might alter things a little, I would think. The malaria parasite( plasmodium protozoa) in a blood smear for instance, is the opposite, with dark m recommended and bright m adding additional details. Perhaps the salinity of the medium has that affect.

As a companion to these wonderful charts is the Nikon website that attempts to explain the difference in all of this.. It may have been posted here in the past, but here it is again for anyone interested...

https://www.microscopyu.com/microscopy- ... objectives

BillT

Apo,

Yes, I heard it depends on refractive index difference between subject and media too. For example, diatom frustules mounted in water can look like a reversed image , in terms of subject brightness, compared to the same mounted in Pleurax.

Thanks, apo, for this rich in detail matrix of phase contrast types/suggested best specimens to observe with...I keenly looked at the suggestions for : large protozoa, small protozoa, and for large bacteria, small bacteria. What a tease..I don't think I found on this use matrix suggestion for: flagella, suggestion for cilia! But there is the delightful tease: B= other specifics better observed (something like that). A very interesting chart, a lot to think about in context of 1948 light microscopy, thank you Apo.

Charlie Guevara with circa 1991 Nikon Labophot-Pol trinoc with dl Phase and BM 20X phase objectives..and a similar : use matrix chart for this 1990's Nikon phase system.

Another note of thanks . . . THANKS!