Diatoms and things...

Charles Krebs · Post by **Charles Krebs** » Sat Aug 11, 2012 9:53 pm

arturoag75 · Post by **arturoag75** » Sat Aug 11, 2012 10:58 pm

.impressive shots

Arturo

Jacek · Post by **Jacek** » Sun Aug 12, 2012 1:04 am

wonderful pictures

Franz Neidl · Post by **Franz Neidl** » Sun Aug 12, 2012 1:37 am

Hello Charles!

congratulation for the pictures! I think the big "things" are Spiculae from Sponges (Poriferans).

Franz

Cactusdave · Post by **Cactusdave** » Sun Aug 12, 2012 1:54 am

Very nice images indeed. They remind me of the images of similar subjects by a well known prize winning photomicrographer with the initials SW and believe me that's meant as a sincere compliment.

Not that I'm jealous or anything.

Some info on objectives and lighting methods would be appreciated. Is that second image Rheinberg? That last one is intriguing too, Rheinberg, or polarisation with a variable retarder?

The 'things' are indeed sponge spiculae, common in fossil diatom strews.

Charles Krebs · Post by **Charles Krebs** » Sun Aug 12, 2012 7:55 am

I was pretty sure they were sponge spicules, but went with "things" to be safe

. There is one more centrally located "spike" pointing directly at the camera.

Some info on objectives and lighting methods would be appreciated.

The first is darkfield with 10X objective (pretty significant crop).

Second is 20/0.70 DIC, with the DIC slider cranked up to "Disney Color" range.

Third is 20/0.70 DIC with DIC slider at a more "normal" setting.

Last one is 40/0.95 DIC, with the slider once again cranked up into a very colorful range.

Frez · Post by **Frez** » Sun Aug 12, 2012 10:58 am

Hi Charles

Terrific images! Disney Color needs to be adopted as a scientific term. I've never noticed the central structure on that type of spicule. Could it be a foreign object?

Frez

Cactusdave · Post by **Cactusdave** » Sun Aug 12, 2012 11:47 am

Thanks Charles. I should have though of 'overcooked' DIC as a source of the colours. Those high NA x20 and X40 objectives are something special. Great sharpness and resolution of detail.

Frez, I have seen that circular 'hub cap' like structure in the centre of spicules several times. I assumed it was where two spicules were joined in the live sponge and had come apart.

Charles Krebs · Post by **Charles Krebs** » Sun Aug 12, 2012 1:54 pm

Well I suppose "optical staining" ( http://www.olympusmicro.com/primer/java ... index.html ) sounds more official, but "Disney Color" works for me

.
(Sort of a derivation from of the name we lovingly gave to Fuji Velvia in the fim days ... Disneychrome).

If you are referring to the part indicated by the arrow:

That is another "branch" identical to the six that are shown, but it is pointed directly into the objective. In this case it was not broken off so I had to be very careful to use enough oil to float the cover slip above it. So what you see in the 20X objective shot is an optical cross section (it gets nearly completely blurred out in the 40X objective shot).

I tried your tip using cassia oil. A few years ago I did something similar with a high RI Cargille Refractive Index Matching Liquids (Series B I think, about 1.70 RI). It worked well, but the stuff was very expensive and did not have a long shelf life. GNC sells the cassia oil for aroma therapy so I thought hey... I'll get some needed therapy and take a few pictures at the same time. It advertised "Benefits: Warming, stimulating, refreshing" (to which I will add, if you work over this stuff all afternoon in a hot, poorly ventilated room "nauseating".

)

Really though it worked well, smells good, and is cheap. I'll use it more often.

Since I did float the cover to avoid breaking the subject I was expecting more image degradation than I experienced. I wonder if the slightly higher RI (about 1.60) helped in this regard. Generally when I use the 20/0.70 through this much liquid (water) I can clearly see the loss in resolution.

Frez · Post by **Frez** » Sun Aug 12, 2012 3:12 pm

What I like about the Cassia oil is that the slide can be nudged a few times and some things turn over and become dislodged from debris. The oil does evaporate slowly. It's easy to refresh with capillary action though. I'm cataloging a sample from Newburyport, MA and have been on the same slide for about 7 days.

Frez

curt0909 · Post by **curt0909** » Mon Aug 13, 2012 3:23 am

2 and 3 are my favorites. On photo #2 are those air pockets or the actual 'pores' of the structure?

naturephoto1 · Post by **naturephoto1** » Mon Aug 13, 2012 7:13 am

Charlie,

Beautiful images.

Rich

Charles Krebs · Post by **Charles Krebs** » Mon Aug 13, 2012 9:31 am

Thanks all for the comments!

On photo #2 are those air pockets or the actual 'pores' of the structure?

Those are pores in the cell wall.

RogelioMoreno · Post by **RogelioMoreno** » Mon Aug 13, 2012 11:58 am

Very nice images!

Rogelio

pierre · Post by **pierre** » Mon Aug 13, 2012 11:29 pm

Very clean pictures: Top!

Thanks Charles