3 more diatoms for a Tuesday night

Charles Krebs · Post by **Charles Krebs** » Tue Mar 11, 2008 11:22 pm

Well... two diatoms and a piece of another.

Cyclops · Post by **Cyclops** » Wed Mar 12, 2008 3:37 pm

Very nice,that last one looks very strange. Crossed polarizers?

Hairyduck · Post by **Hairyduck** » Wed Mar 12, 2008 3:44 pm

last one is using DIC

I agree, fantastic set of images, the second pic was certainly a challenge I guess!

Cyclops · Post by **Cyclops** » Wed Mar 12, 2008 3:58 pm

Hairyduck wrote:last one is using DIC

I agree, fantastic set of images, the second pic was certainly a challenge I guess!

Hmmm need to research what DIC is.

Charles Krebs · Post by **Charles Krebs** » Wed Mar 12, 2008 5:50 pm

Yup, the third image is DIC with a little "twist". I was playing around with some mounting variations. I tried mixing some diatoms with some Canada balsam that I had greatly diluted with xylene. I spread a drop over a cover slip and let it dry. This resulted in diatoms stuck to the slip, but not fully "covered" in mountant. I then put a drop of "normal" consistency Canada balsam on a slide and added the cover slip. (This is all in an effort to find a simple effective method of getting more of the diatoms attached flat against the cover slip). On one slide that I prepared there was an air bubble, and the diatom piece in the third picture above was attached to the cover slip but wound up inside the air bubble. So it is in effect attached to the cover-slip with a thin, uneven layer of balsam. The uneven layer of mountant causes an interesting variation in colors when viewed using DIC. The bubble was basically an accident but I think I may try to use the effect on occasion.

Here's another diatom that wound up in the same situation. You can see that the color variation differs from the "normal" DIC gradation.

Cyclops · Post by **Cyclops** » Thu Mar 13, 2008 2:15 am

DIC = Differential Interference Contrast lighting?

Charles Krebs · Post by **Charles Krebs** » Thu Mar 13, 2008 8:16 am

DIC = Differential Interference Contrast lighting?

Yes.

lauriek · Post by **lauriek** » Thu Mar 13, 2008 12:08 pm

Beautiful (as usual!)

So the third is (twisty) DIC - Are the first two phase contrast?

Cheers!

Hairyduck · Post by **Hairyduck** » Thu Mar 13, 2008 12:53 pm

Cyclops wrote:DIC = Differential Interference Contrast lighting?

also...

DIC = stupidly expensive

Charles Krebs · Post by **Charles Krebs** » Thu Mar 13, 2008 7:02 pm

Laurie,

All three are DIC. You have some ability to vary the "look" from rather monochrome, to the bright colorful rendition of the last two images seen here.