First (my very first one, actually) is a focus stacked image of the very tip of a glass prism (a cornercube, specifically) where the polished surfaces were represented as black. The interesting parts are the ground bevels, where you can see the grinding pits, and with the three-sector Rhienberg, you can tell the local slope directions.
Next up is a single exposure (not stacked) of a moth wing, showing the scales. Ones that had come loose were especially prone to diffraction, so showed up nicely.
And finally, two different focus positions of fossilized radiolaria (dry mounted on black paper). The first is an attempt to focus on one of the fossils, and the second is focused on the background.
I also looked at fresh moss, but it was too 3-D, and focus stacking didn't work too well. So, instead, I made a through focus movie (.gif, 10 MB), which can be accessed at https://lavinia.as.arizona.edu/~mtuell/ ... inberg.gif.
For those with BD/ED/Epi style darkfield objectives, it is pretty easy to do this technique. I used different colors of shim-stock, since I had some, but any transparent colored filters that you can cut into little crescents should work.
Enjoy!
Mike
) is descriptive, but drab. If this actually is a new technique, let it be called (ahem... drum roll please!) 
