Razor blade edge. Reflected DIC

Charles Krebs · Post by **Charles Krebs** » Sat Aug 15, 2009 12:03 pm

One reason I dragged out the BHA was that I finally got a DIC prism for reflected light, and wanted to give it a try. I only have one, and it is for a 20X objective. Tried a few subjects that were at hand. In some cases the "effect" was minimal or nearly non-existent. But the blade edge of this single edged razor blade got very interesting and colorful.

Photographed at 50X using Olympus BHA, vertical illuminator, 20X objective with DIC, 2.5X NFK photo-eyepiece.

ChrisR · Post by **ChrisR** » Sat Aug 15, 2009 4:39 pm

So the blue band is what, a few tens of microns across?
Next question of course is "What is it?"
At first look it resembles the oxide coating which builds up when ground steel gets hot, but I doubt that would be part of the manufacture. A surface treatment then, to provide a hardened edge? Blue - cobalt? Probably not, but perhaps it's written all over the packet!?

Sharp picture, of course

lauriek · Post by **lauriek** » Sat Aug 15, 2009 6:31 pm

Cool shot! It's funny I was just reading up on knife sharpening and 'micro serrations' and then you post a picture of some!

Is this a brand new razor blade? I find the 'fibrous' look of the side of the blade interesting, I guess that's down to how these are ground...

Charles Krebs · Post by **Charles Krebs** » Sun Aug 16, 2009 4:45 pm

This is a slightly used blade. To the eye it has a normal, bright, colorless steel look. The colors are "introduced" by the DIC lighting.

Here's a detailed explanation about what is going on:

http://www.microscopyu.com/articles/dic ... eddic.html