Re: features visible at low magnification are not "clear" at high magnification

I can't tell you much about the "why's", but here is a trick about "how to
make it visible": you just vaporize a very thin layer of carbon with a
vacuum sputtering machine, such as used by SEM and EMP techniques. Your
indentation will become neatly visible under reflected light microscopy.

J.J.


In article <1134956259.142792.17340@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
"sanjiv" <shrivastavas@xxxxxxxxxxxxxxxxxx> wrote:

> Dear microscopist,
>
> I think i have a relatively simple problem for the experts in
> optical microscopy.
>
> I'm looking at indentation in hard ceramics [opaque material] using
> simple optical microscope with x10,x20,x50,x100 using yellow light,
> observing in reflection mode.
>
> The problem I have is at low magnification x10 around the indents a
> ring like feature is visible, however at high magnification x50 or
> x100 the features is not visible. The lateral size of the indents
> ranges from 30um to 200um. measurements by different techniques
> (AFM) the vertical depth of indents range from 2um - expected 15ums.
> The ring like features ranges in height from few(10-50) nanometers
> to about 1ums.
>
>
> I would appreciate comments, literature, references etc. explaining
> this effect.
>
> since, images can not be posted, i would gladly give images for indpeth
> response.
>
>
> thanking you for the help.
>
> Warm regards
> Sanjiv
.