Ted M. Clarke
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Here are some images of Chrysotile
asbestos in 1.550HD mountant that show use of this technology for mineral
"The plane polarized darkfield image shows the characteristic dispersion staining color and this method works near the limit of the resolving power of the microscope. These images have not been published but might be in the future. Optical dispersion staining at this resolution has never been done before. These images of the same field were taken using the LOMO 60 X 1.00 NA oil immersion apochromat using my modified LOMO Biolam. My punched polymer film analyzer and red wave plate work very well, are cheap and easy to make.They also precisely orient in the plastic sliders."
A darkfield image of a Chrysotile asbestos specimen in 1.550HD index mountant.
"You can see that the oil immersion 1.25 NA objective can be used at full resolution without a funnel stop using darkfield above 1.25 NA provided by the LOMO 1.40 NA condenser with the right size stop. I see no need for me to own a darkfield condenser, especially when none of them have a high enough NA to use with a 1.25 NA objective without a funnel stop to reduce the NA to 1.0. The digital images are intended to show the subjects as they appear through the eyepieces. The default settings of the Nikon CoolPix 995 digital camera are used without subsequent enhancement, although adjusting contrast and reducing brightness can improve the darkfield images."