Immersion oil

My Zeiss immersion oil ran out. No worries, I had another one. This one was Olympus. And as it turned out, a bit thinner. And viscosity of immersion oil is quite a critical characteristic when using an inverted microscope.

On the bottles I can't find any kind of direct information about the viscosity, strange enough. The refractive index is mentioned, though. Also a very critical phenomenon. Zeiss had it 0,002 higher than Olympus. That shall not make the difference.

Again, while visiting the Netherlands, my dear colleague and a the Great Microscope Man René van Wezel told me a thing or two about the secret life of immersion oil. Here you can find some more information on the subject: Cargille and Olympus.

So it became clear that I will stick to Type B immersion oil with a higher viscosity, 1250 centistokes (cSt or mm2/s) as it is called. I might even try the NVH type with the viscosity of 21000 cSt.