Vendor reply

Gisela,

Based on my own Masters thesis work with cylindrical hydrogels, the effects
you are seeing are a result of light being diffracted differently in
different regions of the bubble surface.  Think of light passing through a
lens, and look particularily at the rays passing through the exact center
(no diffraction) and rays passing through the periphery (the ray is bent
quite dramatically).

I know of no way to get rid of the effect, but if you send me a few images,
I would be happy to look at them and make suggestions.  In my own research,
I was actually able to use this effect to make my analysis easier...

Chris

Chris Tully
Digital Imaging Specialist
A.G.Heinze, Inc.
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-----Original Message-----
From: Confocal Microscopy List
[mailto:[log in to unmask]]On Behalf Of Gisela
Richardson
Sent: Tuesday, April 24, 2001 8:14 AM
To: [log in to unmask]
Subject: Optical effects in foams


Dear confocal users,
When I study foam structures with a large amount of air bubbles,
these are not homogeneously black in the confocal microscope.
The bubbles often get a bright ring just inside the bubble surface.
Where two bubbles lie closely, this ring is darker, where the bubble
is surrounded by other materia such as fat, protein, water phase
etc, the ring gets brighter.
Is this an optical phenomenon due to reflection in the phase
boundaries or an effect of the section thickness? My bubbles have
a diameter of about 20 um in the section, and I use a 100x
objective.
Does anyone know how to get rid of this annoying ring if the
images are used for image analysis?

Best regards,
Gisela Richardson
Ph D student
SIK - The Swedish Institute for Food Research