Re: [ATM] Zernike (or Lyot) phase contrast tests

[u.suessenberger@t-online.de ("Uwe Süßenberger")]

Hello Guy,

From: "Guy Brandenburg" <gfbrandenburg@yahoo.com>
> How many people have ever performed one of those
> Zernike Phase Contrast Tests to examine surface
> roughness? I have just been reading about them in Best
> of ATMJ #2 and it all looks fairly easy to make, and
> rather useful and informative as well. There is just
> one problem: It says that if you want to make a
> photograph, you have to make 10-MINUTE exposures with
> Kodalith film!!! That must mean that the images are
> EXCEEDINGLY dim...

afaik, the kodalith is not used for taking an image of the surface-roughness but it serves as a screen on which a 0.1mm bar is been used as phase-shifting-device. Instead of kodalith you may use TP 2415. For construction details see:
http://home.t-online.de/home/wolfgang.rohr/phaskont.htm
The phase-contrast image itself may be taken with any (digital-) camera.

Kind Regards: Uwe
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