MicrobeHunter.com Microscopy Forum

A couple of shots from an antique slide labeled
Circle Group
Diatomeceae
Walfisch Bay
S. Africa
Styrax

Olympus IX70 10x HMC EOS 7D
Seven image stack


Olympus IX70 10x HMC EOS 7D
Fifteen image stack


Enjoy
Radazz

That is an interesting slide. Any chance you can get a bit closer to some of the diatoms.

75RR wrote:That is an interesting slide. Any chance you can get a bit closer to some of the diatoms.

Sure. I was concerned more with the composition.
Which did you have in mind?
Radazz

Thanks. The second largest in the first image if you can. Like the star shape in the center

Here it is, 75
30x HMC (300x)

Not a star after all.


Saw this one while looking for the one you wanted. 4 image stack


Radazz

Thanks, those are great images. Fantastic detail.

Not a star after all.

Indeed. Have to admit I am surprised though, still, can't argue with the larger image.

What structure causes this splendid spectrum of colors? it is not common among diatoms, is it?

I think it may be refraction. I see much more brilliant colors with phase contrast or HMC, but even closing the iris in brightfield will bring out some color.
I also see more color in antique diatom slides than in brand new slides.
It’s possible that the mountant and it’s age affect things as well.

I know nothing,
Radazz

I was wondering if the rows of tiny holes (punctae?), so close together, might be acting like a diffraction grating, separating the colors like the reflections of light sources off a CD-ROM disk, which can be used as a poor man's diffraction grating?

But the colors disappear under high magnification, and I don't know if that would happen with a diffraction grating.

How well the sample is cleaned could matter a great deal.
I ordered one of Klaus’ 8 forms test slides, we’ll see what perfect specimens look like.
Radazz