Why it's good to process diatoms...

The top photo is the final product, the real thing: processed diatoms (it took hours!), permanently mounted (flush to the cover slip) with a special high-refractive index mounting medium (dried for two days at the time the photo was taken), and photographed at 1000x magnification.

The bottom photo was taken a year ago of a similar, but living, diatom in pond water. It's also at 1000x. Now, my overall technique has improved in the past year so I could perhaps take a better picture of a similar diatom today, but still, you get the idea. There is no way a live picture, in water, could give you the detail on the frustule (diatom shell) that you get in the top photo. The problems are mainly:

1) organic material obscures the detail
2) the specimens are thicker (in life) and so harder to focus on with high magnification
3) the R.I. of water is too low (I can't explain much of the physics of this but I'm working on it!)
4) the water mounted material is spread all over a rather great distance between the slide and cover slip, while the permanent mount material is flush to the cover slip, giving a much more uniform depth of field over the entire slide, making focus much more consistent

You may be getting the impression that I'm pretty excited about this--that would be correct. These photos really validate a project I've been working on this semester in my chemistry class, and I'm very pleased to have gotten good results!