Money (with apologies to Pink Floyd)   Leave a comment

I was hoping to capture a timelapse auto-fluorescent series of our cells undergoing division, but for various reasons it didn’t work out- he cells divide once every 8 hours, and after 5 hours under the microscope, nothing had happened. Which in experimental science, is the case more often than not.

So instead, here’s another magnification series: one of the back of a $2 bill, since there’s a few tiny faces to explore, and the second of the front of a new-ish US nickle. First, the paper money- zooming in until the paper fibers are more prominent than the drawing, and at maximum magnification, individual dots of ink can be discerned (but possibly not in the de-scaled images I posted here).

Personally, I think the guy all the way on the left of picture #3 is freaky-looking.

Now for the nickel- again, a similar set of images. So far, the only real change occurs when I switch from oblique to epi-illumination- notice the contrast greatly increases.

But wait- there’s more. One of the powerful techniques in microscopy is Differential Interference Contrast (DIC), which also goes by several aliases: ICT, Interphako, etc. In reflection imaging, DIC converts height into color. Here three images taken with this technique, using the 4X and 16X epiplan objective- notice the brilliant color present.

Also of note are the two images taken at 16X- what was done is to slide one of the optical components ever so slightly; this changes the ‘bias’ of the image, and is used to emphasize particular parts of the image.

The reason the colors at 16X are so much more vivid than 4X, is that the height variation of the object matches the depth of field of the 16X lens better. At lower magnifications (and lower numerical apertures), the height variation is barely detectable. At higher magnifications, the height variations are significantly greater than the depth of field, and so most of the image appears blurry (which is also why I didn’t include any).

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Posted September 10, 2010 by resnicklab in pic of the moment

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